RikoteMaster/aqua-rat-mcqa huggingface dataset:
Question: What is the measure of the angle E made by the diagonals of the any adjacent sides of a cube.
A.30
B.45
C.60
D.75
Answer: C.60
Explanation: C.. 60 degrees
All the diagonals are equal. If we take 3 touching sides and connect their diagonals, we form an equilateral Triangle. Therefore, each angle would be 60..C
Question: Pens, Pencils and Markers in a Jenna's desk are in the ratio of 2: 2 : 5. If there are 10 Pens, the number of Markers in Jenna's desk is:
A.30
B.22
C.20
D.25
Answer: D.25
Explanation: Explanation :
Let Pens = 2x, Pencils = 2x & Markers = 5x. Now, 2x = 10 hence x = 5.
Number of markers = 5x which is 25.
Answer : D
Question: Convert the following unit:
5 hectares in mÂ²
A.50000 mÂ²
B.40000 mÂ²
C.60000 mÂ²
D.70000 mÂ²
Answer: A.50000 mÂ²
Explanation: 5 hectares in mÂ²
1 hectare = 10000 mÂ²
Therefore, 5 hectares = 5 Ã— 10000 mÂ²
= 50000 mÂ²
ANSWER : OPTION A
Question: How many times are the hands of a clock at right angle in a day?
A.22
B.24
C.44
D.32
Answer: C.44
Explanation: In 12 hours, they are at right angles 22 times.
In 24 hours, they are at right angles 44 times.
Answer: Option C
Question: A train of 30 carriages, each of 60 meters length, when an engine also of 60 meters length is running at a speed of 60 kmph. In what time will the train cross a bridge 1.5 km long?
A.4
B.3.3
C.5
D.7
Answer: B.3.3
Explanation: D = 30 * 60 + 1500 = 3300 m
T = 3300/60 * 18/5 = 198 sec = 3.3 mins
Answer: B
Question: The population of a bacteria culture doubles every 6 minutes. Approximately how many minutes will it take for the population to grow from 1,000 to 500,000 bacteria
A.10
B.12
C.14
D.54
Answer: D.54
Explanation: This one's easy.
1000 * 2^t = 500,000
2^t = 500
Now gauging, since 2^8 = 256, then 2^9 = 512
So t = 9
But be careful, 't' is in time intervals of 6 minutes
So answer is 9* 6 = 54 minutes
Answer (D)
Question: Working alone, Mary can pave a driveway in 3 hours and Hillary can pave the same driveway in 6 hours. When they work together, Mary thrives on teamwork so her rate increases by 10%, but Hillary becomes distracted and her rate decreases by 20%. If they both work together, how many hours will it take to pave the driveway?
A.2 hours
B.4 hours
C.5 hours
D.6 hours
Answer: A.2 hours
Explanation: Initial working rates:
Mary = 1/3 per hour
Hillary = 1/6 per hour
Rate when working together:
Mary = 1/3 + (1/10*1/3) = 3/8 per hour
Hillary = 1/6 - (1/5*1/6) = 2/15 per hour
Together they work 3/8 + 2/15 = 1/2 per hour
So they will need 2 hours to complete the driveway. The correct answer is A.
Question: Two pipes A and B can fill a cistern in 12 and 15 minutes respectively. Both are opened together but after 3 minutes A is turned off. After how much more time will the cistern be filled?
A.8 1/8
B.8 1/9
C.8 1/4
D.8 1/1
Answer: C.8 1/4
Explanation: 3/12 + (3 + x)/15 = 1
x = 8 1/4
Answer:C
Question: Four horses are tethered at four corners of a square plot of side 63 metres so that they just cannot reach one another. The area left ungrazed is:
A.675.5m2
B.780.6m2
C.785.8m2
D.850.5m2
Answer: D.850.5m2
Explanation: Required area= (63*63 – 4*1/4 *22/7 * 63/2 * 63/2)= 850.5m2 ANSWER:D
Question: A rectangular photograph is surrounded by a border that is 1 inch wide on each side. The total area of the photograph and the border is M square inches. If the border had been 5 inches wide on each side, the total area would have been (M + 180) square inches. What is the perimeter of the photograph, in inches?
A.21
B.36
C.38
D.40
Answer: A.21
Explanation: Let Length and Breadth of photograph be L and B respectively.
Perimeter is given by 2*(L+b) -----(1)
According to the question:
(L+2)(B+2) = m ----(2)
and
(L+10)(B+10) = m + 180 ---------> (L+10)(B+10) - 180 = m ------(3)
Equating (2) and (3)
(L+2)(B+2) = (L+10)(B+10) - 180
LB + 2L + 2B + 4 = LB + 10L + 10B + 100 -180
Simplify
8L + 8B = 84 ------> 2(L+B) = 21 (Check eq (1))
Answer is A
Question: If the letters of the word PLACE are arranged taken all at a time, find how many do not start with AE.
A.110
B.114
C.115
D.119
Answer: B.114
Explanation: Total no'of arrangements 5P5 = 5! = 120
no'of arrangements start with AE = 1 × 6 = 6
no'of arrangements which do not start with AE = 120 - 6 = 114.
B
Question: A man can row upstream at 8kmph and downstream at 13 kmph. The speed of the stream is?
A.3kmph
B.2.5kmph
C.3.5kmph
D.4.3kmph
Answer: B.2.5kmph
Explanation: Speed of stream = 1/2 (13-8) = 2.5kmph
Answer is B
Question: Fresh fruit contains 68% water and dry fruit contains 20% water. How much dry fruit can be obtained from 100 kg of fresh fruits ?
A.10Kg
B.20Kg
C.30Kg
D.40Kg
Answer: D.40Kg
Explanation: The fruit content in both the fresh fruit and dry fruit is the same.
Given, fresh fruit has 68% water.so remaining 32% is fruit content. weight of fresh fruits is 100kg
Dry fruit has 20% water. so remaining 80% is fruit content. let weight if dry fruit be y kg.
fruit % in fresh fruit = fruit% in dry fruit
(32/100) * 100 = (80/100 )* y
we get, y = 40 kg
Answer :D
Question: Find the fourth proportion to 3,12,4
A.18
B.16
C.10
D.12
Answer: B.16
Explanation: Explanation:
3:12:: 4:x
=> 3/12 = 4/x
=> x = 48/3
=> x = 16
Option B
Question: c and d represents 2 train stations which are 320 km apart. If 2 trains leave each station and travel towards each other at what time will they meet each other, given that the first train left the station at 11 a.m. and travels at a speed of 85 kmph while the second train left the station at 12 p.m. and travels at a speed of 75 kmph.
A.1.00 p.m
B.2.00 p.m
C.12.00 p.m
D.12.30 p.m
Answer: C.12.00 p.m
Explanation: Suppose they meet x hours after 11 a.m.
Distance moved by first train in x hours + distance moved by 2nd train in x-1 hrs = 320
85x+75(x-1) = 320
85x+75x-75= 320
160x= 320
x = 2
So they meet 2 hr after 10 a.m. which is at 12.00 p.m.
Answer is C
Question: A library has an average of 175 visitors on Sundays and 75 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is :
A.80
B.90
C.100
D.110
Answer: B.90
Explanation: Explanation:
Since the month begins with a Sunday, so there will be five Sundays in the month,
Required average = (165 * 5 + 75 * 25) / 30 = 2700/30 = 90
Answer: B) 90
Question: Tickets for all but 100 seats in a 10,000-seat stadium were sold. Of the tickets sold, 15% were sold at half price and the remaining tickets were sold at the full price of $2. What was the total revenue from ticket sales?
A.$15,840
B.$17,820
C.$18,000
D.$18,315
Answer: D.$18,315
Explanation: 10000 seats --> Full Price : Half Price = 8500 : 1500
Price when all seats are filled = 17000 + 1500 = 18500
100 seats are unsold --> Loss due to unfilled seats = 15 + 2*85 = 185
Revenue = 18500 - 185 = 18315
Answer: D
Question: If the average cost of a house was $50,000 in 1965 and was x in 2005, what was the average increase in home prices per year over this period?
A.(x+50,000)/40
B.(x-50,000)/40
C.(50,000/40)+x
D.(50,000-x)/40
Answer: B.(x-50,000)/40
Explanation: Average house price in 2005: x
Average house price in 1965: 50,000
2005-1965=40
Average increase per year: (x-50,000)/40
Answer is B
Question: Suppose you have access to a large vat of distilled water, several gallons large. You have two precise measuring pipettes, one to measure exactly 1/4 of an ounce and one to measure exactly 1/5 of an ounce. You can pour precisely measured amounts into a beaker, which initially is empty. You can use either pipette to remove distilled water from the vat or from the beaker and use either pipette to dispense water into either of those receptacles, but you cannot use either pipette to take any quantity of distilled water other than the amount for which it is designed. Which of the following represents, in ounces, a precise amount of distilled water you can transfer from the vat to the beaker?
I. 1/6
II. 1/7
III. 1/12
A.I only
B.1/20 and 9/20
C.I and III only
D.II and III only
Answer: B.1/20 and 9/20
Explanation: 1/4-1/5=1/20
1/4+1/5=9/20
Answer: B
Question: A train is running at a speed of 40 km/hr and it crosses a post in 16.2 seconds. What is the length of the train?
A.190 metres
B.160 metres
C.200 metres
D.120 metres
Answer: B.160 metres
Explanation: Speed of the train, v = 40 km/hr = 40000/3600 m/s = 400/36 m/s
Time taken to cross, t = 16.2 s
Distance Covered, d = vt = (400/36)Ã— 16.2 = 160 m
Distance covered is equal to the length of the train = 160 m
Correct answer is 160 metres
B
Question: The two trains of lengths 400 m, 600 m respectively, running at same directions. The faster train can cross the slower train in 180 sec, the speed of the slower train is 48 km. then find the speed of the faster train?
A.22
B.68
C.26
D.28
Answer: B.68
Explanation: Length of the two trains = 600m + 400m
Speed of the first train = X
Speed of the second train= 48 Kmph
1000/X - 48 = 180
1000/x - 48 * 5/18 = 180
50 = 9X - 120
X = 68 Kmph
Answer: B
Question: How many such 3's are there in the following number sequence which are immediately Preceded by an odd number and immediately followed by an even number? 5 3 8 9 4 3 7 2 3 8 1 3 8 4 2 3 5 7 3 4 2 3 6
A.1
B.2
C.3 three
D.4
Answer: C.3 three
Explanation: A is followed by B means : A comes first,B comes next
A precede d by B means : B comes first, A comes next
The sets which satisfy the condition is: 5 3 8
1 3 8
7 3 4
ANSWER:C
Question: What sum of money put at C.I amounts in 2 years to Rs.7000 and in 3 years to Rs.9261?
A.4000
B.8877
C.2877
D.2678
Answer: A.4000
Explanation: 7000 ---- 2261
100 ---- ? => 32.3%
x *1323/100 * 1323/100 = 7000
x*1.75=7000
x=7000/1.75 => 3999.25
Answer: A
Question: All of the students of Music High School are in the band, the orchestra, or both. 80 percent of the students are in only one group. There are 136 students in the band. If 60 percent of the students are in the band only, how many students are in the orchestra only?
A.33
B.39
C.34
D.42
Answer: C.34
Explanation: % of students in one group only = 80%
% of students in both groups = 100 - 80 = 20%
% of students in the band only = 60%
Number of students who are in band = 136
20% + 60% = 80% = 136 Students
Finding total students:
x = (136 x 100)/80
x = 170
Students in orchestra only = 170 - 136 = 34
Answer:C
Question: A chair is bought for Rs.120/- and sold at Rs.240/- find gain or loss percentage
A.115% loss
B.120% gain
C.125% gain
D.100% gain
Answer: D.100% gain
Explanation: Formula = (Selling price ~ Cost price)/Cost price * 100
= (240- 120)/120 = 100% gain
D
Question: A, B, C and D enter into partnership. A subscribes 1/3 of the capital B 1/4, C 1/5 and D the rest. How much share did A get in a profit of Rs.2460?
A.29999
B.26676
C.29986
D.14000
Answer: D.14000
Explanation: 25*12: 30*12: 35*8
15:18:14
14/47 * 47000 = 14000
Answer: D
Question: The average (arithmetic mean) of eight numbers is 44.1. If the sum of half of these numbers is 158.4, what is the average of the other half?
A.12.8
B.24.2
C.48.6
D.72.1
Answer: C.48.6
Explanation: arithmetic mean = sum / total numbers
sum = 44.1 * 8 = 352.8
sum of half of these numbers is 158.4. So, 4 numbers sum is 158.4. Rest 4 numbers sum = 352.8-158.4 = 194.4
Arithmetic mean of the 4 nos = 194.4/4 = 48.6
Hence, C is the answer.
Question: The price of the jewel, passing through three hands, rises on the whole by 80%. If the first and the second sellers 20% and 25% profit respectively find the percentage profit earned by the third seller.
A.20
B.10
C.15
D.25
Answer: A.20
Explanation: Let the original price of the jewel be $ p and let the profit earned by the third seller be x% Then, (100+x)% of 125% of 120% of P =180% Of P ((100+X)/100*125/100*120/100*P)=(180/100*P)
==> (100+X)=(180*100*100)/(125*120)=120=>X=20%
Answer A
Question: Which of the following is greatest?
A.1/2
B.1/4
C.1/3
D.1/6
Answer: A.1/2
Explanation: simply we know that 1/2 is greater than all others.
So, Answer : A
Question: Ron walks to a viewpoint and returns to the starting point by his car and thus takes a total time of 6 hours 45 minutes. He would have gained 2 hours by driving both ways. How long R would it have taken for him to walk both ways.
A.8 h 45 min
B.7 h 45 min
C.6 h 45 min
D.5 h 30 min
Answer: A.8 h 45 min
Explanation: 1.Walking to to a viewpoint+Driving back=6 hours 45 minutes
2.Driving to a viewpoint+Driving back=6 hours 45 minutes - 2 hours=4 hours 45 minutes, thereforeone way driving=4 hours 45 minutes/2 =2 hours 22.5 minutes.
3. From 1.one way driving=6 hours 45 minutes-2 hours 22.5 minutes=4 hours 22.5 minutes.
4.Walking to to a viewpoint+Walking back R=4 hours 22.5 minutes+4 hours 22.5 minutes=8 hours 45 minutes.
Answer: A.
Question: A work can be finished in 14 days by thirty women. The same work can be finished in fifteen days by forteen men. The ratio between the capacity of a man and a woman is
A.3:4
B.4:3
C.2:1
D.3:2
Answer: C.2:1
Explanation: Work done by 20 women in 1 day = 1/14
Work done by 1 woman in 1 day = 1/(14Ã—30)
Work done by 14 men in 1 day = 1/15
Work done by 1 man in 1 day = 1/(15Ã—14)
Ratio of the capacity of a man and woman =1/(15Ã—14) : 1/(14Ã—30) = 1/15 : 1/30
= 1/3 :1/6 = 1/1=1/2=2:1
Answer is C
Question: A train moves fast a telegraph post and a bridge 264 m long in 8 sec and 20 sec respectively. What is the speed of the train?
A.5/6 km/hr
B.25 km/hr
C.79.2 km/hr
D.15 km/hr
Answer: C.79.2 km/hr
Explanation: Explanation:
Let the length of the train be x m and its speed be y m/sec.
Then, x/y = 8 => x = 8y
(x + 264)/20 = y
y = 22
Speed = 22 m/sec = 22 * 18/5 = 79.2 km/hr
Answer:C
Question: A train passes a station platform in 36 seconds and a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, what is the length of the platform?
A.228 m
B.240 m
C.227 m
D.167 m
Answer: B.240 m
Explanation: Speed = (54 * 5/18) m/sec = 15 m/sec. Length of the train = (15 x 20)m
= 300 m. Let the length of the platform be x meters. Then, (x + 300)/36 = 15 ==> x + 300 = 540 ==> x
= 240 m.
Answer: B
Question: The public library has exactly 2 floors. It has 3/4 as many shelves on its 2nd floor as it does on its 1st. If the second floor has 5/6 as many books per shelf as the first floor, what fraction of the library's books are on the first floor?
A.24/39
B.5/14
C.5/9
D.9/14
Answer: A.24/39
Explanation: Let x be the no of shelves and y be the no of books per shelf on first floor.
Now no of shelves on 2nd floor = (3/4)*x
no of books per shelf on 2nd floor = (5/6) * y
So total no books on first floor = xy and total no of books on 2nd floor = (3/4)*x*(5/6)*y = (15/24)*xy
fraction of library books on first floor = (xy)/(xy + (15/24)*xy)
=1 / (1+(15/24))
=24/39
So A
Question: If p / q is an integer, which of the following statements must be true?
A.p = nq where n is an integer
B.both p and q are integers
C.q / p is an integer
D.either p or q is negative
Answer: A.p = nq where n is an integer
Explanation: Let p = 1/4; q = 1/8 --> p/q = 2
p = nq where n is an integer --> 1/4 = 2*(1/8) --> Correct
Answer: A
Question: The population of a bacteria colony doubles every day. If it was started 6 days ago with 2 bacteria and each bacteria lives for 12 days, how large is the colony today?
A.64
B.128
C.256
D.512
Answer: B.128
Explanation: 2^6(2) = 2^7 = 128
The answer is B.
Question: A bowl contains equal numbers of red, orange, green, blue, and yellow candies. Kaz eats all of the green candies and half of the orange ones. Next, he eats half of the remaining pieces of each color. Finally, he eats red and yellow candies in equal proportions until the total number of remaining candies of all colors equals 25% of the original number. What percent of the red candies remain?
A.10%
B.15%
C.25%
D.35%
Answer: C.25%
Explanation: Let x be the original number of each color.
Kaz eats all of the green candies and half of the orange ones.
There are 0 green candies and 0.5x orange candies remaining.
He eats half of the remaining pieces of each color.
There are 0.25x orange candies, and 0.5x each of red, yellow, and blue candies.
He eats red and yellow candies in equal proportions.
orange+blue+red+yellow = 0.75x + red + yellow = 1.25x
red + yellow = 0.5x
red = 0.25x, since red = yellow.
The answer is C.
Question: A train ride from Two P to Town Q costs $2.35 more than does a bus ride from Town P to Town Q. Together, the cost of one train ride and one bus ride is $9.85. What is the cost of a bus ride from Town P to Town Q?
A.$1.25
B.$2.50
C.$3.75
D.$4.70
Answer: C.$3.75
Explanation: Let x be the cost of a bus ride.
x + (x+235) = 985
2x = 750
x = $3.75
The answer is C.
Question: Square A has an area of 25 square centimeters. Square B has a perimeter of 12 centimeters. If square B is placed within square A and a random point is chosen within square A, what is the probability the point is not within square B?
A.9/25
B.1/5
C.16/25
D.3/5
Answer: C.16/25
Explanation: I guess it's mean that square B is placed within square Aentirely.
Since, the perimeter of B is 12, then its side is 12/4=3 and the area is 3^2=9
Empty space between the squares is 25-9=16 square centimeters, so if a random point is in this area then it won't be within square B: P=favorable/total=16/25.
Answer: C
Question: What are the unit and symbol for current?
A.WW
B.776
C.26
D.68
Answer: D.68
Explanation: Answer: Option D
Question: Three taps A, B and C can fill a tank in 12, 15 and 20 hours respectively. If A is open all the time and B and C are open for one hour each alternately, the tank will be full is?
A.6 hrs
B.8 hrs
C.7 hrs
D.3 hrs
Answer: C.7 hrs
Explanation: (A + B)'s 1 hour work = (1/12 + 1/15) = 3/20
(A + C)'s 1 hour work = (1/12 + 1/20) = 2/15
Part filled in 2 hrs = (3/20 + 2/15) = 17/60
Part filled in 6 hrs = 3 * 17/60 = 17/20
Remaining part = 1 - 17/20 = 3/20
Now, it is the turn of A and B and 3/20 part is filled by A and B in 1 hour.
Total time taken to fill the tank = (6 + 1) = 7 hrs.Answer: C
Question: 10 men can complete a piece of work in 15 days and 15 women can complete the same work in 12 days. If all the 10 men and 15 women work together, in how many days will the work get completed?
A.6
B.6 1⁄3
C.6 2⁄3
D.7 2⁄3
Answer: C.6 2⁄3
Explanation: 10 men’s 1 day’s work = 1⁄15
15 women’s 1 day’s work = 1⁄12
(10 men + 15 women)’s 1 day’s work
= (1⁄15 + 1⁄12) = 9⁄60 = 3⁄20
∴ 10 men and 15 women will complete the work in 20⁄3 = 62⁄3 days.
Answer C
Question: Rohan spends 40% of his salary on food, 20% on house rent, 10% on entertainment and 10% on conveyance. If his savings at the end of a month are Rs. 1500. then his monthly salary is
A.Rs. 6000
B.Rs. 7500
C.Rs. 8000
D.Rs. 10,000
Answer: B.Rs. 7500
Explanation: Sol.
Saving = [100 - (40 + 20 + 10 + 10]% = 20%.
Let the monthly salary be Rs. x.
Then, 20% of x = 1500
⇔ 20 / 100x = 1500
⇔ x = 1500 × 5 = 7500.
Answer B
Question: (4300631)-?=2535618
A.1865113
B.1775123
C.1765013
D.1675123
Answer: C.1765013
Explanation: Let 4300631-x=2535618
then x=4300631-2535618
=1765013
Answer is C
Question: A box contains 3 blue marbles, 4 red, 6 green marbles and 2 yellow marbles. If four marbles are picked at random, what is the probability that none is blue?
A.33/98
B.33/91
C.33/92
D.33/96
Answer: B.33/91
Explanation: Given that there are three blue marbles, four red marbles, six green marbles and two yellow marbles. When four marbles are picked at random, then the probability that none is blue is = ¹²C₄/¹⁵C₄
= (12 * 11 * 10 * 9)/(15 * 14 * 13 * 12)
= 33/91
Answer:B
Question: Krishna's monthly expenditure was decreased by 50% and subsequently increased by 50%. How much percent does he loss?
A.25 %
B.50 %
C.75 %
D.85 %
Answer: A.25 %
Explanation: Explanation :
Let the original expenditure = Rs. 100.
New final expenditure = 150% of (50% of Rs. 100)
= Rs.(150/10050/100100)
= Rs. 75.
Decrease = 100- 75 = 25 %
Answer : A
Question: In a school with 5 classes, each class has 2 students less then the previous class. How many students are there in the largest class if the total number of students at school is 95?
A.17
B.19
C.21
D.23
Answer: D.23
Explanation: Total classes = 5
Total students = 95.
Average = 19
If the classes had average number of students: 19 19 19 19 19
Given case = 23 21 19 17 15
Hence number of students in the largest class = 23
Correct Option: D
Question: A lent Rs. 5000 to B for 2 years and Rs. 3000 to C for 4 years on simple interest at the same rate of interest and received Rs. 2200 in all from both of them as interest. The rate of interest per annum is?
A.16%
B.12%
C.74%
D.10%
Answer: D.10%
Explanation: Let the rate be R% p.a. Then,
(5000 * R * 2)/100 + (3000 * R * 4)/100 = 2200
100 R + 120 R = 2200
R = 10%
Answer:D
Question: A merchant gains or loses, in a bargain, a certain sum. In a second bargain, he gains 280 dollars, and, in a third, loses 20. In the end he finds he has gained 120 dollars, by the three together. How much did he gain or lose bv the first ?
A.80
B.-140
C.140
D.120
Answer: B.-140
Explanation: In this sum, as the profit and loss are opposite in their nature, they must be distinguished by contrary signs. If the profit is marked +, the loss must be -.
Let x = the sum required.
Then according to the statement x + 280 - 20 = 120
And x = -140.
Answer B
Question: Five bells begin to toll together and toll respectively at intervals of 6, 5, 7, 10 and 12 seconds. How many times will they toll together in one hour excluding the one at the start ?
A.7 times
B.8 times
C.9 times
D.11 times
Answer: B.8 times
Explanation: Explanation:
L.C.M. of 6, 5, 7, 10 and 12 is 420.
So, the bells will toll together after every 420 seconds i.e. 7 minutes.
Now, 7 x 8 = 56 and 7 x 9 = 63.
Thus, in 1-hour (or 60 minutes), the bells will toll together 8 times, excluding the one at the start.
Answer: B
Question: Find the sum lend at C.I. at 5 p.c per annum will amount to Rs.441 in 2 years?
A.198
B.400
C.268
D.267
Answer: B.400
Explanation: 441
= P(21/20)2
P = 400
Answer:B
Question: Set J consists of the terms {a, b, c, d, e}, where e > d > c > b > a > 3. Which of the following operations would decrease the standard deviation of Set J?
A.Multiply each term by e/d
B.Divide each term by b/c
C.Multiply each term by −1/2
D.Divide each term by d/e
Answer: C.Multiply each term by −1/2
Explanation: CONCEPT: Standard Deviation is Defined as Average Deviation of Terms in the set from the Mean value of the set. i.e.
1) It depends on the separation between the successive terms of the set
2) If a Constant Value is Added/Subtracted in every terms of set then the Separation between successive terms does NOT change Hence S.D. remains Constant
3) If a Constant Value is Multiplied in every terms then the Separation between succesive terms gets multiplied by the constant Hence S.D. remains gets multiplied by same Number
C
Question: The population of a town is 7900. It decreases annually at the rate of 10% p.a. What was its population 2 years ago?
A.9750
B.8000
C.8500
D.9500
Answer: A.9750
Explanation: Formula :
( After =100 denominator
Ago = 100 numerator)
7900 Ã— 100/90 Ã— 100/90 = 9753
A)
Question: Two trains are running at 40 km/hr and 20 km/hr respectively in the same direction. Fast train completely passes a man sitting in the slower train in 9 sec. What is the length of the fast train?
A.27 7/6
B.27
C.27 7/2
D.50
Answer: D.50
Explanation: Relative speed = (40 - 20) = 20 km/hr.
= 20 * 5/ 18 = 50/9 m/sec.
Length of faster train = 50/9 * 9 = 50 m
Answer:D
Question: When 0.252525...........is converted into a fraction, then find the result.
A.25/99
B.25/90
C.25/999
D.25/9999
Answer: A.25/99
Explanation: Answer
0.252525 ..... = 0.25= 25/99
Correct Option: A
Question: To apply for the position of photographer at a local magazine, a photographer needs to include three or four photos in an envelope accompanying the application. If the photographer has pre-selected seven photos representative of her work, how many choices does she have to provide the photos for the magazine?
A.54
B.60
C.64
D.70
Answer: D.70
Explanation: 7C3 + 7C4 = 35 + 35 = 70
The answer is D.
Question: A can do a work in 7 days and B in 12 days. If they work on it together then in how many days required to complete the work?
A.83/19
B.84/19
C.81/19
D.77/19
Answer: B.84/19
Explanation: Person ( A ) ( B ) ( A+B )
Time - ( 7 ) ( 12 ) (84/19)
Rate - ( 12 ) ( 7 ) ( 19 )
Work - (84) ( 84 ) ( 84 )
therefore A+B requires (84/19) days to complete entire work
= 84/19
Answer is B