Rationale: S = (200 + 300)/45 = 500/45 * 18/5 = 40
The answer: (D)
Question: A train 200 meters long completely crosses a 300 meters long bridge in 45 seconds. What is the speed of the train is?
Options:
(A) 10
(B) 20
(C) 30
(D) 40
(E) 50
Reasoning: There were 36*5 = 180 total votes made. If each voter picked 3 coaches, there were 180/3 = 60 voters.
Ans: (A)
Question: The rowing athletes in a rowing conference voted for coach of the year. Each rower who voted chose exactly 3 coaches to vote for among the 36 coaches in the conference. If each of the 36 coaches received exactly 5 votes (a 36 way tie), how many rowers voted for coach of the year?
Options:
(A) 60
(B) 70
(C) 75
(D) 84
(E) 90
Rationale: Let B be turned off after x minutes. Then, Part filled by (A + B) in x min. + Part filled by A in (30 -x) min. = 1. x(2/75 + 1/45) + (30 - x). 2/75 = 1 11x/225 + (60 - 2x)/75 = 1 11x + 180 - 6x = 225. x = 9.
The answer: (A)
Question: Two pipes A and B can fill a cistern in 37 minutes and 45 minutes respectively. Both pipes are opened. The cistern will be filled in just half an hour, if the B is turned off after:
Options:
(A) 9 minutes
(B) 7
(C) 6
(D) 5
(E) 4
Reasoning: The intersection for two = 45 - 12 - 22 = 11 play both games.
Ans: (C)
Question: 45 pupil,out of them 12 in debate only and 22 in singing only.then how many in both?
Options:
(A) 9
(B) 10
(C) 11
(D) 12
(E) 13
Rationale: P(at last 1 tails) = 1 - P(all heads) = 1 - (1/2)^3 = 7/8.
The answer: (D)
Question: The probability is 1/2 that a certain coin will turn up heads on any given toss. If the coin is to be tossed three times, what is the probability that on at least one of the tosses the coin will turn up tails?
Options:
(A) 1/8
(B) 1/2
(C) 3/4
(D) 7/8
(E) 15/16
Rationale: Increase = (60/120)*100 = (1/2)*100 = 50%.
The answer: (C)
Question: Henry earns $120 a week from his job. His income increased and now makes $180 a week. What is the percent increase?
Options:
(A) 70%
(B) 60%
(C) 50%
(D) 40%
(E) 30%