Reasoning: 12
12 4 + 2 = 50
50 4 + 2 = 202
202 4 + 2 = 810
810 4 + 2 = 3242
3242 4 + 2 = 12970
Ans: (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
Rationale: Part filled by A + B + C in 1 hour = 1/5 + 1/10 + 1/30 = 1/3
All the three pipes together will fill the tank in 3 hours.
The answer: (C)
Question: Pipe A can fill a tank in 5 hours, pipe B in 10 hours and pipe C in 30 hours. If all the pipes are open, in how many hours will the tank be filled?
Options:
(A) 5
(B) 4
(C) 3
(D) 6
(E) 8
Reasoning: 20 m/s = 20 * 18/5 kmph
3 hours 45 minutes = 3 3/4 hours = 15/4 hours
Distance = speed * time = 20 * 18/5 * 15/4 km = 270 km.
Ans: (D)
Question: If a man can cover 20 metres in one second, how many kilometres can he cover in 3 hours 45 minutes?
Options:
(A) 288
(B) 162
(C) 220
(D) 270
(E) 122
Rationale: From 0 to 9999 there are 10000 four digit numbers
So maximum number of unsuccessful attempts = 10000 - 1 = 9999
The answer: (B)
Question: Maximum no of unsuccessful attempts, a thief can do in order to break a number locking system of 4 digits.
Options:
(A) 9988
(B) 9999
(C) 9799
(D) 9685
(E) 6545
Reasoning: 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.
Ans: (C)
Question: The no. of girls in a class are 7times the no. of boys, which value cannever be the of total students?
Options:
(A) 20
(B) 35
(C) 30
(D) 40
(E) 42
Reasoning: If the number is divisible by 11, then the alternate digits' sum must be divisible by 11 or difference is 0. Only 1 yields such a number.
Ans: (A)
Question: The number N is 5,H48, where H represents the hundred's digit. If N is divisible by 11, what is the value of H
Options:
(A) 1
(B) 7
(C) 6
(D) 5
(E) 2