RikoteMaster/aqua-rat-mcqa huggingface dataset:
Question: Albert borrowed a total of $ 6000 from Brian and Charlie. He paid simple interest at the rate of 7 % Per yr and 9 % per yr respectively.At the end of three years he paid $ 1494 as total interest. What is the interest paid to Brian at the end of three years?
A.$210
B.$630
C.$441
D.$694
Answer: C.$441
Explanation: Money from Brian = x
Money from Charlie = 6000 -x
1494 = 3 [ x (0.07) + (6000-x) (0.09)]
Solve for x, x = 2100
Interest paid to Brian = 2100 * 0.07 * 3 = 441
ANSWER:C
Question: In a rectangular coordinate system, if a line passes through the points (-15,-18), (15,22) and (x,2) then what is the value of x?
A.-2
B.-1
C.0
D.1
Answer: C.0
Explanation: The slope of the line m is rise/run = 22-(-18) / 15-(-15) = 4/3
4/3 = 22-2 / 15-x
60-4x = 66-6
x = 0
The answer is C.
Question: A sum was put at simple interest at a certain rate for 10 years . Had it been put at 5% higher rate , it would have fetched Rs.400 more. What was the Sum?
A.s.1200
B.s.800
C.s.1400
D.s.1000
Answer: B.s.800
Explanation: At 5% more rate, the increase in S.I for 10 years = Rs.400 (given)
So, at 5% more rate, the increase in SI for 1 year = 400/10 = Rs.40/-
i.e. Rs.40 is 5% of the invested sum
So, 1% of the invested sum = 40/5
Therefore, the invested sum = 40 × 100/5 = Rs.800 Answer: B
Question: Two trains of length 180 m and 280 m are running towards each other on parallel lines at 42 kmph and 30 kmph respectively. In what time will they be clear of each other from the moment they meet?
A.22 sec
B.23 sec
C.76 sec
D.20 sec
Answer: B.23 sec
Explanation: Relative speed = (42 + 30) * 5/18 = 4 * 5 = 20 mps.
Distance covered in passing each other = 180 + 280 = 400 m.
The time required = d/s = 460/20 = 23 sec.
Answer:B
Question: A dog is tied to a tree by a long nylon cord. If the dog runs from the due North side of the tree to the due South side of the tree with the cord extended to its full length at all items, and the dog ran approximately 30 feet, what was the approximate length of the nylon cord E, in feet?
A.30
B.25
C.15
D.10
Answer: D.10
Explanation: Because the cord was extended to its full length at all items, the dog ran along a semi-circular path, from north to south.
The circumference of a full circle is 2*pi*r, but since we only care about the length of half the circle, the semi-circle path is pi*r.
E=pi*r = 30. Round pi = 3, then r = 10.
Chord is about 10 feet long.D
Question: Two cylinders are of the same height. Their radii are in the ratio 1: 3. If the volume of the first cylinder is 40 cc. Find the volume of the second cylinder?
A.360 cc
B.60 cc
C.300 cc
D.36 cc
Answer: A.360 cc
Explanation: r1 = x r2 = 3x
Π * x2 * h = 40
Π9 x2h = 40 * 9 = 360
ANSWER:A
Question: Tough and Tricky questions: Number Properties.
If (z + 3)/7 is an integer, what is remainder when z is divided by 7?
A.2
B.3
C.4
D.5
Answer: D.5
Explanation: Assume the answer choices as the value of z
7/7=1
Ans D
Question: K and L are each four-digit positive integers with thousands, hundreds, tens, and units digits defined as a, b, c, and d, respectively, for the number K, and p, q, r, and s, respectively, for the number L. For numbers K and L, the function W is defined as 5^a*2^b*7^c*3^d ÷ 5^p*2^q*7^r*3^s. The function Z is defined as (K – L) ÷ 10. If W = 16, what is the value of Z?
A.16
B.20
C.25
D.40
Answer: D.40
Explanation: K = 1000a + 100b + 10c + d
L = 1000p + 100q + 10r + s
also W = 16 = 2^4 now when u equate this value
u will get a=p c=r d=s and b-q = 4 as u will have to equate the powers.
now put that in value of z you will get 10*4 = 40
ANSWER:D
Question: Ayesha's father was 38 years of age when she was born while her mother was 36 years old when her brother four years younger to her was born. What is the difference between the ages of her parents?
A.1 years
B.7 years
C.6 years
D.8 years
Answer: C.6 years
Explanation: Mother's age when Ayesha's brother was born = 36 years.
Father's age when Ayesha's brother was born = (38 + 4) = 42 years.
Required difference = (42 - 36) = 6 years.
Answer: C
Question: What is the sum of all possible solutions to |x - 3|^2 + |x - 3| = 30 ?
A.4
B.5
C.3
D.2
Answer: B.5
Explanation: Denote |x - 3| as y: y^2 + y = 30 --> y = -6 or y = 5. Discard the first solution since y = |x - 3|, so it's an absolute value and thus cannot be negative.
y = |x - 3| = 5 --> x = 8 or x = -3. The sum = 5.
Answer: B.
Question: A collection of books went on sale, and 2/3 of them were sold for $4.25 each. If none of the 30 remaining books were sold, what was the total amount received for the books that were sold?
A.$260
B.$255
C.$285
D.$290
Answer: B.$255
Explanation: If 30 books constitute 1/3rd of the total, then 2/3rd of the total = 60 books
Amount received for sold books = 60 * 4.25 = $255
Answer : B
Question: If abc ≠ 3 and the sum of the reciprocals of a, b, and c equals the reciprocal of the product of a, b, and c, then a =
A.(1 + bc)/(b + c)
B.(1 – bc)/(b + c)
C.(1 + b + c)/(bc)
D.(1 – b – c)/(bc)
Answer: D.(1 – b – c)/(bc)
Explanation: Answer is D though it took me around 4 minutes to get that.
Question: Ashley and Vity work on a sales staff with 8 other salespeople. If five members of the staff will be chosen at random to attend a sales workshop, what is the probability that both Ashley and Vity will be chosen?
A.1/10
B.3/28
C.2/9
D.1/4
Answer: C.2/9
Explanation: I did slightly different and hence obviously ended up with the answer 2/9.
I assumed that because Ashley and Vity have to be chosen, the remaining selection is 3 people from 8.
8C3/10C5= 2/9. Option C.
Question: A women purchased a sofa and a bed for Rs. 12000 &Rs. 8000 respectively. He sold the sofa at a loss of 9% and the bed at a profit of 14%. Overall how much he make a profit.
A.20
B.10
C.30
D.50
Answer: B.10
Explanation: Let the SP of the refrigerator and the mobile phone be Rs. r and Rs. m respectively.
r = 12000(1 - 9/100) = 12000 - 1080
m = 8000(1 + 14/100) = 8000 + 1120
Total SP - Total CP = r + m - (12000 + 8000) = -1080 + 1120 = Rs.40
As this is positive, an overall profit of Rs. 40 was made.
B
Question: An order was placed for a carpet whose length and width were in the ratio of 3 : 2. Subsequently, the dimensions of the carpet were altered such that its length and width were in the ratio 4 : 1 but were was no change in its perimeter. What is the ratio of the areas of the carpets?
A.5:8
B.3:2
C.6:1
D.8:7
Answer: B.3:2
Explanation: Let the length and width of one carpet be 3x and 2x.
Let the length and width of the other carpet be 4y and y.
2(3x + 2x) = 2(4y + y)
5x = 5y
x = y
The ratio of the areas of the carpet in both cases:
= 3x * 2x : 4y * y
= 6x^2 : 4y^2
= 6x^2 : 4x^2
= 6 : 4
= 3 : 2
The answer is B.
Question: A boy has Rs. 160 in the denominations of one-rupee notes, five-rupee notes and ten-rupee notes. The number of notes of each denomination is equal. What is the total number of notes that he has ?
A.30
B.110
C.140
D.130
Answer: A.30
Explanation: Let number of notes of each denomination be x.
Then x + 5x + 10x = 160
16x = 160
x = 10.
Hence, total number of notes = 3x = 30.
A
Question: A person purchased a TV set for Rs. 16000 and a DVD player for Rs. 6250. He sold both the items together for Rs. 31150. What percentage of profit did he make?
A.30%
B.35%
C.40%
D.45%
Answer: C.40%
Explanation: The total CP = Rs. 16000 + Rs. 6250 = Rs. 22250 and SP = Rs. 31150
Profit(%) = (31150 - 22250)/22250 * 100 = 40%
ANSWER:C
Question: How many multiples of 9 are there between 18 and 270 ?
A.12
B.27
C.42
D.61
Answer: B.27
Explanation: It should be mentioned whether 18 and 270 are inclusive.
If 18 and 270 are inclusive, then the answer is (270-18)/9+1=29.
If 18 and 270 are NOT inclusive, then the answer is (261-27)/9+1=27.
Since OA is B, then we have NOT inclusive case.
Question: Jim drove 768 miles of a 1200 miles journey. How many more miles does he need to drive to finish his journey?
A.113 miles
B.432 miles
C.456miles
D.887 miles
Answer: B.432 miles
Explanation: The number of miles to drive to finish his journey is given by
1200 - 768 = 432 miles
correct answer B
Question: A train covers a distance in 50 min ,if it runs at a speed
of 48kmph on an average.The speed at which the train must run
to reduce the time of journey to 40min will be.
A.60kmph
B.63kmph
C.57kmph
D.70kmph
Answer: A.60kmph
Explanation: Time=50/60 hr=5/6hr
Speed=48mph
distance=S*T=48*5/6=40km
time=40/60hr=2/3hr
New speed = 40* 3/2 kmph= 60kmph
Answer is A.
Question: Each child has 2 pencils and 13 Skittles. If there are 15 children, how many pencils are there in total?
A.30
B.12
C.18
D.22
Answer: A.30
Explanation: 2*15=30.Answer is A.
Question: What is the least number which should be added to 2982 so that the sum is exactly divisible by 5, 6, 4, and 3?
A.14
B.18
C.22
D.26
Answer: B.18
Explanation: L.C.M. of 5, 6, 4 and 3 = 60.
When dividing 2982 by 60, the remainder is 42.
The number to be added = 60 - 42 = 18.
The answer is B.
Question: A can finish a work in 18 days and B can do same work in half the time taken by A. then working
together, what part of same work they can finish in a day
A.1\5
B.1\6
C.1\7
D.1\8
Answer: B.1\6
Explanation: Explanation:
Please note in this quesƟon, we need to answer part of work for a day rather than complete work. It was
worth mentioning here because many do mistake at this point in hurry to solve the question
So lets solve now,
A's 1 day work = 1/18
B's 1 day work = 1/9 [because B take half Ɵme than A]
(A+B)'s one day work =
(118+19)=(1+218)=16
So in one day 1/6 work will be done
Answer: B
Question: A and B can do a piece of work in 7 days, B and C in 8 days, C and A in 9 days. How long will C take to do it?
A.14.1 days
B.18.8 days
C.21.4 days
D.24.3 days
Answer: C.21.4 days
Explanation: 2c = 1/8 + 1/9 – 1/7 = 47/504
c = 47/1008 => 1008/47 = 21.4 days
The answer is C.
Question: If the radius of a circle is decreased by 50%, find the percentage decrease
A.22
B.099
C.75
D.26
Answer: C.75
Explanation: Let original radius = R.
New radius = =
Original area = and new area =
Decrease in area = = 75%
Answer: C
Question: At the wholesale store you can buy an 8-pack of hot dogs for $1.55, a 20-pack for $3.05, and a 250-pack for $22.95. What is the greatest number of hot dogs you can buy at this store with $203?
A.1,108
B.2,100
C.2,108
D.2,120
Answer: D.2,120
Explanation: I think it should be D.
I can buy 8 250-pack for Rs 22.95*8 = $183.60
Now, I can buy 6 20-pack for 3.05*5 = $18.30
Now, I am left with only $1.15. I cannot but anything with this.
Hence Total Hotdogs = 250*8 + 20*5 = 2120
Question: If the tens digit of positive integer x is 6 and the tens digit of positive integer y is 6, how many possible values of the tens digit of 2(x+y) can there be?
A.2
B.3
C.4
D.5
Answer: C.4
Explanation: We only need to consider the tens and ones digits of x and y, and the last two digits can be represented as 60 + p and 60 + q respectively.
2(60+p+60+q)= 240 + 2(p + q).
2(p+q) can range from 0 up to a maximum value of 36 when p=q=9.
Then the tens and ones digits of 2(x+y) can range from 40 up to 76.
There can be 4 possibilities for the tens digit.
The answer is C.
Question: The sum of two numbers is 25 and their difference is 13. Find their product.
A.104
B.114
C.315
D.325
Answer: B.114
Explanation: Let the numbers be x and y.
Then x + y = 25 and x - y = 13.
x = 19; y = 6
xy = 19 * 6 = 114
ANSWER:B
Question: Consider the sequence of numbers beginning 23, 27, 28, 32, 33... It continues in such a way that by adding 5 to the nth term, one obtains the (n + 2)th term. What is the sum of the first 14 members of this sequence?
A.878
B.900
C.560
D.928
Answer: C.560
Explanation: I would split them up like this.
23 28 33 and so on (7 terms)....the 7th term = 23+6*5 = 53
27 32 37 and so on (7 terms)......the 7th term = 27+6*5 = 57
Since the distance between any two numbers is the same we can use arithmetics
first+last/2 times no of numbers = the sum
(23+53)/2 * 7 =266
(27+57)/2 * 7 = 294
= 560
C
Question: If Jesse flips a coin seven times in a row, what is the probability that the result will not be tails for more than 2 times?
A.21/128
B.29/128
C.35/128
D.1/16
Answer: B.29/128
Explanation: Not more than 2 times tails = at least 5 times heads
Atleast 5 heads in 7 flip.
The total outcome of flip is = 2^7 = 128
For any Coins problem write the ask in the shown format.
HHHHHTT
HHHHHHT
HHHHHHH
Once you have written in the above mentioned format the answer is pretty straight.
HHHHHTT = [7!]/5!*2! = 21
HHHHHHT = [7!]/6! = 7
HHHHHHH = [7!]/[7!] = 1
Sum = 21+7+1 = 29/128
Answer - B
Question: In the xy-coordinate system, if (m, n) and (m + 1, n + k) are two points on the line with the equation x = 2y + 5, then k =
A.1/2
B.1
C.2
D.5/2
Answer: A.1/2
Explanation: Since (m, n) and (m + 2, n + k) are two points on the line with the equation x = 2y + 5 they should satisfy m=2n +5 and m+1 =2 *(n+k)+5.
By 1st equation we have m-2n=5 and by 2nd equation m-2n = 2k+4 ---> 5=2k+4 --->k=1/2.
The answer is, therefore, (A).
Question: Deepa started a business in 2009 by investing Rs.50,000. She invested Rs. 20,000 as additional amount in 2010 and her friend Sushma joined her with an amount of Rs.70,000. Deepa invested another Rs. 20,000 in 2011 and Avanthi joined them with Rs. 70,000. At the end of these 3 years, they earned a profit of Rs. 3,00,000. Find Sushma's share ?
A.Rs.1,00,229
B.Rs.1,00,209
C.Rs.1,00,012
D.Rs.1,00,000
Answer: D.Rs.1,00,000
Explanation: Deepa invested Rs.50,000 for 12 months, Rs.(50000 + 20000) for 12 months and Rs.(50000 + 20000 + 20000) for 12 months.
i.e, she invested Rs.50,000 for 12 months, Rs.70000 for 12 months and Rs.90000 for 12 months.
Sushma invested Rs. 70000 for 2 years; i.e, Rs.70000 for 24 months
And, Avanthi invested Rs.70000 for 1 year; i.e, Rs. 70000 for 12 months.
Their investing ratio:
Deepa : Sushma : Avanthi = (50,000 x 12 + 70000 x 12 + 90000 x 12):(70000 x 24):(70000 x 12)
= (25,20,000):(16,80,000):(8,40,000) = 252:168:84 = 3:2:1
Total profit for 3 years = Rs.3,00,000
Therefore, Sushma's share = Rs.(3,00,000 x 2 /(3+2+1)) = Rs.(3,00,000 x 2/6) = Rs.1,00,000.
Answer: D
Question: The ratio of the volumes of two cubes is 8: 27 What is the ratio of their total surface areas?
A.2:4
B.3:6
C.4:12
D.4:9
Answer: D.4:9
Explanation: Ratio of the sides = Â³âˆš8 : Â³âˆš27
= 2 : 3
Ratio of surface areas =4:9
Answer: D
Question: A man sells an article at a profit of 25%. If he had bought it at 20% less and sold it for Rs.12.60 less, he would have gained 30%. Find the cost of the article.
A.30
B.40
C.50
D.60
Answer: D.60
Explanation: Let C.P=100
Gain=25%
S.P=125
Supposed C.P=80
Gain=30%
S.P=(130*80)/100=104
Diff=(125-104)=21
Diff 21 when C.P=100
then Diff 12.60 when C.P=(100*12.60)/21=60
ANSWER:D
Question: A snooker tournament charges $40.00 for VIP seats and $15.00 for general admission (“regular” seats). On a certain night, a total of 300 tickets were sold, for a total cost of $7,500. How many fewer tickets were sold that night for VIP seats than for general admission seats?
A.190
B.180
C.150
D.200
Answer: D.200
Explanation: let no of sits in vip enclosure is x then x*40 +15( 300-x) =7500 or 25x = 7500 -4500 , x = 3000/25 =120
vip =120 general 200
D
Question: In a sports club with 28 members, 17 play badminton and 19 play tennis and 2 do not play either. How many members play both badminton and tennis?
A.7
B.8
C.9
D.10
Answer: D.10
Explanation: Let x play both badminton and tennis so 17-x play only badminton and 19-x play only tennis. 2 play none and there are total 30 students. hence,
(17-x)+(19-x)+x+2=28
38-2x+x=28
38-x=28
x=10
So 8 members play both badminton and tennis.
D
Question: Look at this series: 15, 15, ?, 27, 39, 39, ... What number should fill the blank?
A.51
B.39
C.27
D.15
Answer: C.27
Explanation: Explanation: In this simple addition with repetition series, each number in the series repeats itself, and then increases by 12 to arrive at the next number.
Answer: Option C
Question: Compound interest earned on a sum for the second and the third years are Rs.1200 and Rs.1440 respectively. Find the rate of interest?
A.27%
B.28%
C.20%
D.16%
Answer: C.20%
Explanation: Rs.1440 - 1200
= Rs.240 is the interest on Rs.1200 for one year.
Rate of interest
= (100 * 240) / (100 * 1)
= 20% p.a
Answer: C
Question: A trader sells 20 meters of cloth for Rs. 4500 at the profit of Rs. 10 per metre of cloth. What is the cost price of one metre of cloth?
A.Rs. 380
B.Rs. 215
C.Rs. 190
D.Rs. 395
Answer: C.Rs. 190
Explanation: SP of 1m of cloth = 4500/20= Rs. 225
CP of 1m of cloth = SP of 1m of cloth - profit on 1m of cloth
= Rs. 225 - Rs. 10 = Rs. 215.
ANSWER:C
Question: A train with 1200m crosses a tree in 120sec, how much time will I take to pass a platform 700m long?
A.150sec
B.130sec
C.190sec
D.200sec
Answer: C.190sec
Explanation: s=1200/120
s-10m/sec
total length = 1900m
t=d/s
t=1900/10
t=190sec
ANSWER C
Question: When Usha was thrice as old as Nisha, her sister Asha was 25, When Nisha was half as old as Asha, then sister Usha was 34. their ages add to 100. How old is Usha?
A.10
B.20
C.30
D.40
Answer: D.40
Explanation: Asha=25 Nisha =n Usha =3n
Asha=2a Nisha =a Usha =34
The difference of all ages must be same
25-2a=n-a=3n-34
We will get two equation
2n+a=34
n+a=25
From the equation we will get n=9 and a=16
The ages are Asha=2a=32 Nisha =16 and Usha =34
Sum of the ages =100
(32+x)+(16+x)+(34+x)=100
82+3x=100
3x=18
x=6
Age of Usha =34+6=40
ANSWER:D
Question: A and B start a business jointly. A invests Rs.16000 for 8 months and B remains in the business for 4 months. Out of the total profit B claims 3/7th share. How much money is contributed by B?
A.A)Rs.12829
B.B)Rs.12800
C.C)Rs.24000
D.D)Rs.12804
Answer: C.C)Rs.24000
Explanation: 16*8: x*4 = 4:3
x = 24 =>
Rs.2400
Answer: C
Question: A shipment of 240 smartphones contains 84 that are defective. If a customer buys two smartphones at random from the shipment, what is the approximate probability that both phones are defective?
A.1/250
B.9/74
C.1/11
D.1/9
Answer: B.9/74
Explanation: Probability of chosing one defective phone from a lot of 240 which ontains 84 defective phones is = (84/240)
Probability of chosing one defective phone from a lot of 239(we already picked one) which ontains 83(we already picked one) defective phones is = (83/239)
Combined probability of series of events = product of the probabilities = (84/240)*(83/239)
84/240 is close to (7/20) and (83/239)= (25/72)
so answer is (7/20)*(25/72) (9/74)
So, answer will be B
Question: A circular ground whose radius is 15 metres, has a 1.2 metre-broad garden around it. What is the area of the garden in square metres?
A.118.67
B.116.67
C.117.67
D.120.56
Answer: C.117.67
Explanation: Req. area = Ï€[(16.2)2 â€“ (15)2]
= 22â„7 Ã— (31.2 Ã— 1.2)[since a2 - b2 = (a + b)(a - b)]
= (22 Ã— 31.2 Ã— 1.2)/7 = 117.67sq m
Answer C
Question: An amount of Rs. 100000 is invested in two types of shares. The first yields an interest of 9% p.a and the second, 11% p.a. If the total interest at the end of one year is 9 3/4 %, then the amount invested in each share was?
A.37507
B.37500
C.83887
D.29978
Answer: B.37500
Explanation: Let the sum invested at 9% be Rs. x and that invested at 11% be Rs. (100000 - x). Then,
(x * 9 * 1)/100 + [(100000 - x) * 11 * 1]/100 = (100000 * 39/4 * 1/100)
(9x + 1100000 - 11x)/100 = 39000/4 = 9750
x = 62500
Sum invested at 9% = Rs. 62500
Sum invested at 11% = Rs. (100000 - 62500) = Rs. 37500.
Answer:B
Question: A fair red coin with sides marked heads and tails is to be tossed eight times. What is the probability that the coin will land tails side up more than five times?
A.A)37/256
B.B)56/256
C.C)65/256
D.D)70/256
Answer: A.A)37/256
Explanation: Landing on tails more than 5 times means tails has to hit 6, 7 or 8 times.
8!/6!2! = 7*4 = 28
8!/7!1! = 8
8!/8! = 1
28 + 8 + 1 = 37/256
ans:A
Question: Three 6 faced dice are thrown together. The probability that no two dice show the same number on them is?
A.5/5
B.5/9
C.5/1
D.5/7
Answer: B.5/9
Explanation: No two dice show same number would mean all the three faces should show different numbers. The first can fall in any one of the six ways. The second die can show a different number in five ways. The third should show a number that is different from the first and second. This can happen in four ways.
Thus 6 * 5 * 4 = 120 favourable cases.
The total cases are 6 * 6 * 6 = 216.
The probability = 120/216 = 5/9.
Answer: B
Question: A box contains six bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that at least one bulb is good?
A.21/81
B.16/81
C.65/81
D.2/3
Answer: C.65/81
Explanation: Required probability
= 1 - 16/81
= 65/81
Answer: C
Question: An industrial loom weaves 0.128 metres of cloth every second. Approximately, how many seconds will it take for the loom to weave 25 metre of cloth ?
A.194 seconds
B.195 seconds
C.196 seconds
D.197 seconds
Answer: B.195 seconds
Explanation: Explanation:
Let the time required by x seconds.
Then, More cloth means More time (Direct Proportion)
So,
0.128:1::25:x=>x=25∗1 /0.128
=>x=195.31
So time will be approx 195 seconds
Option B
Question: A train 150 m long can cross an electric pole in 3 sec and then find the speed of the train?
A.180
B.120
C.72
D.27
Answer: A.180
Explanation: Length = Speed * time
Speed = L/T
S = 150/3
S = 50 M/Sec
Speed= 50*18/5 (To convert M/Sec in to Kmph multiply by 18/5)
Speed = 180 Kmph
Answer:A
Question: A certain deck of cards contains 2 white cards, 2 red cards, 2 yellow cards, and 2 green cards. If two cards are randomly drawn from the deck, what is the probability that they will both be not white?
A.15/28
B.1/4
C.9/16
D.1/32
Answer: A.15/28
Explanation: The question asks they will both be not white. Considering that these are draws without replacement there are following possibilities :
draw 1, draw 2
===== =====
1) Not white, white;
2) white, Not white;
3) white, white;
4) Not white, not white;
The answer has to be either P(4) OR all exclusion of the 3 previous conditions i.e. 1- [P(1) + P(2) + P(3)] => neither of the draws are white
P(4) = 6/8*5/7=15/28
1- [P(1) + P(2) + P(3)] = 1 - [ (6/8 * 2/7) + (2/8*6/7) + (2/8*1/7)] = 1 - [26/8*7] = 1 - [13/28] = 15/28
A
Question: A man rows his boat 85 km downstream and 45 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?
A.1 kmph
B.6 kmph
C.5 kmph
D.8 kmph
Answer: D.8 kmph
Explanation: Speed downstream = d/t = 85/(2 1/2) = 34 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (34 - 18)/2 = 8 kmph
Answer:D
Question: A box contains 3red, 5yellow and 4 green balls. 3 balls are drawn randomly. What is the probability that the balls drawn contain balls of different colours?
A.2/7
B.3/11
C.1/4
D.3/7
Answer: B.3/11
Explanation: Total number of balls = 3+5+4 = 12
n(S) = 12C3 = 12*11*10/3*2 = 220 n(E) = 3C1*5C1*4C1 = 3*5*4 = 60 P(E) = 60/220 = 3/11 Answer is B
Question: The average of 13 numbers is 60. Average of the first 7 of them is 57 and that of the last 7 is 61. Find the 8th number?
A.46
B.28
C.25
D.22
Answer: A.46
Explanation: Sum of all the 13 numbers = 13 * 60 = 780
Sum of the first 7 of them = 7 * 57 = 399
Sum of the last 7 of them = 7 * 61 = 427
So, the 8th number = 427 + 399 - 780
=46.
Answer: A
Question: Rs.1500 is divided into two parts such that if one part is invested at 6% and the other at 5% the whole annual interest from both the sum is Rs.84. How much was lent at 5%?
A.299
B.466
C.578
D.600
Answer: D.600
Explanation: (x*5*1)/100 + [(1500 - x)*6*1]/100 = 84
5x/100 + 90 – 6x/100 = 84
x/100 = 6
=> x = 600
Answer:D
Question: Tough and Tricky questions: Probability.
Medical analysts predict that a quarter of all people who are infected by a certain biological agent could be expected to be killed for each day that passes during which they have not received an antidote. What fraction of a group of 1,000 people could be expected to be killed if infected and not treated for three full days?
A.16/81
B.37/64
C.2/3
D.19/27
Answer: B.37/64
Explanation: At the end of each day we will have 3/4 alive. So after 3 days we will have (3/4)^3 people alive. Therefore, fraction of dead people will be 1-(3/4)^3=37/64.
The correct answer is B.