Reasoning: Number of times wheel moves in 1 hour = 12 * 60 = 1200
:. Distance moves = (1200*15) cms = 18000 cms
In metres = 180 metre
Ans: (C)
Question: A wheel rotates 20 times every minute and moves 15 cm during each rotation. How many metres does the wheel move in one hour?
Options:
(A) 6 metre
(B) 18 metre
(C) 180 metre
(D) 1200 metre
(E) 130 metre
Rationale: Hint: y^2-5 (y is an integer) is never multiple of 3 (try to prove this), hence 30 is out.
The answer: (B)
Question: For some integer y, y^2 - 5 is divisible by all of the following EXCEPT
Options:
(A) 29
(B) 30
(C) 31
(D) 38
(E) 41
Reasoning: Speed = 60*(5/18) m/sec = 50/3 m/sec
Length of Train (Distance) = Speed * Time
(50/3) * 6 = 100 meter
Ans: (C)
Question: A train running at the speed of 60 km/hr crosses a pole in 6 seconds. Find the length of the train.
Options:
(A) 150 m
(B) 145 m
(C) 100 m
(D) 135 m
(E) 155 m
Rationale: Time taken by the birds to meet = 10/(4 + 1) = 2 mins
Distance traveled by the bird traveling from West-Town = 4 * 2 = 8
The answer: (B)
Question: The distance between West-Town to East-Town is 10 kilometers. Two birds start flying simultaneously towards one another, the first leaving from West-Town at a speed of 4 kilometers per minute and the second bird, leaving from East-Town, at a speed of 1 kilometers per minute. What will be the distance, in kilometers, between the meeting point and West-Town?
Options:
(A) 3.
(B) 8.
(C) 10.
(D) 12.
(E) 15.
Reasoning: Speed = 30*(5/18) m/sec = 25/3 m/sec
Length of Train (Distance) = Speed * Time
(25/3) * 9 = 75 meter
Ans: (A)
Question: A train running at the speed of 30 km/hr crosses a pole in 9 seconds. Find the length of the train?
Options:
(A) 75
(B) 65
(C) 25
(D) 288
(E) 212
Reasoning: (60/100) * 50 (30/100) * 30
30 - 9 = 21
Ans: (A)
Question: How much 60% of 50 is greater than 30% of 30?
Options:
(A) 21
(B) 91
(C) 11
(D) 17
(E) 12