Rationale: Time = Distance/Speed
120/60 = 2
The answer: (D)
Question: A truck traveled 120 km with a speed of 60 kmh. How much time did it take to reach the destination?
Options:
(A) 3 hours
(B) 4 hours
(C) 5 hours
(D) 2 hours
(E) 6 hours
Reasoning: Let number of boys = x
Let number of girls = y
Therefore x/y = B and y/x = G
3(B + G) = 3[(x/y) + (y/x)] = 3[(x2 + y2)/xy] > 3
Ans: (C)
Question: If the ratio of boys to girls in a class is B and the ratio of girls to boys is G; then 3 (B + G) is ?
Options:
(A) Equal to 3
(B) Less than 3
(C) More than 3
(D) Less than 1/3
(E) none of these
Rationale: Number of ways of selecting 3 people out of 10 people = 10C3
In the three members George will always be there in the team. At this step we have vacancy for 2 more members and 9 members are available. Lina cannot be there in the team. So 2 members have to be selected and the number of available members = 9 - Nina = 8
Number of ways to form a 3 member team that includes George and excludes Nina = 8C2
Probability = 8C2/10C3 = 28/120
The answer: (C)
Question: From a Group of 10 People, Including George and Nina, 3 people are to be selected at random to work on a certain project. What is the probability that 3 people selected will include George but not Nina
Options:
(A) 5/56
(B) 9/56
(C) 28/120
(D) 21/56
(E) 25/56
Reasoning: Cone curved surface area = rl = 22/7 4 5 = 440/7 = 62 6/7
Slant height (l) = r(power2)+h(power2) = 16+9 = 25 = 5
Ans: (C)
Question: The radius of a cone is 4 m, height 5 m. Find the curved surface area?
Options:
(A) 1
(B) 3
(C) 5
(D) 7
(E) 9
Rationale: Sum of the ages of the group having 4 persons and average 40 = 4x40 = 160
Sum of the ages of the group having 5 persons and average 38 = 5x38 = 190
Age of the new person added to the group = 190-160 = 30
The answer: (C)
Question: If we need to change the average age of a group containing 4 persons from 40 to 38 by adding a person. What should be the age of the person newly added to the group?
Options:
(A) 20
(B) 25
(C) 30
(D) 38
(E) 40
Rationale: Sum of all the 13 results = 13 * 20 = 260
Sum of the first 7 of them = 8 * 20 = 160
Sum of the last 7 of them = 8 * 40 = 320
So, the 8th number = 260 + 160 - 320 = 100.
The answer: (E)
Question: The average of 13 result is 20. Average of the first 8 of them is 20 and that of the last 8 is 40. Find the 8th result?
Options:
(A) 35
(B) 37
(C) 46
(D) 90
(E) 100