Rationale: Let the boys are X, then girls are 7X, total = X+7X = 8X
So it should be multiple of 8, 30 is not a multiple of 8.
The answer: (C)
Question: The no. of girls in a class are seven times the no. of boys, which value cannever be the of total students?
Options:
(A) 10
(B) 15
(C) 30
(D) 34
(E) 36
Reasoning: T = 60/36 * 18/5 = 6 sec
Ans: (B)
Question: In what time will a railway train 60 m long moving at the rate of 36 kmph pass a telegraph post on its way?
Options:
(A) 9 sec
(B) 6 sec
(C) 8 sec
(D) 10 sec
(E) 11 sec
Rationale: 12
12 4 + 2 = 50
50 4 + 2 = 202
202 4 + 2 = 810
810 4 + 2 = 3242
3242 4 + 2 = 12970
The answer: (C)
Question: What number comes next in the following number series? 12, 50, 202, 810, 3242, _____
Options:
(A) 12400
(B) 12800
(C) 12970
(D) 13015
(E) 16000
Reasoning: S = (100 + 300)/45 = 400/45 * 18/5 = 32
Ans: (A)
Question: A train 100 meters long completely crosses a 300 meters long bridge in 45 seconds. What is the speed of the train is?
Options:
(A) 32
(B) 545
(C) 88
(D) 66
(E) 09
Rationale: Here both numbers are less than 100. So they are deficient of - 4 and - 1 compared with 100. So
The answer: (E)
Question: Find 96 98
Options:
(A) 93/198
(B) 93/12
(C) 93/13
(D) 93/10
(E) 93/8
Rationale: Work done by the waste pipe in 1 minute = 1/15 - (1/20 + 1/24) = - 1/40
Volume of 1/40 part = 3 gallonsVolume of whole = 3 * 40 = 120 gallons.
The answer: (C)
Question: Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is?
Options:
(A) 820 gallons
(B) 128 gallons
(C) 120 gallons
(D) 129 gallons
(E) 220 gallons