Reasoning: 6a2 = 6 * 2a * 2a = 24a2
Ans: (D)
Question: The edge of a cube is 2a cm. Find its surface?
Options:
(A) 23a2 cm2
(B) 84a2 cm2
(C) 64a2 cm2
(D) 24a2 cm2
(E) 14a2 cm2
Rationale: Speed = 63 * 5/18 = 35/2 m/sec
Time taken = 280 * 2/35 = 16 sec
The answer: (B)
Question: A train 280 m long, running with a speed of 63 km/hr will pass a tree in?
Options:
(A) 15 sec
(B) 16 sec
(C) 18 sec
(D) 20 sec
(E) 25 sec
Reasoning: 2/3 * 6/7 * 1/3 * 1/9 = 12/567 = 4/189
Ans: (C)
Question: The compound ratio of 2/3, 6/7, 1/3 and 1/9 is given by?
Options:
(A) 7/98
(B) 1/48
(C) 4/189
(D) 1/96
(E) 1/68
Rationale: 200/72 * 18/5 = 10 km/hr
The answer: (A)
Question: A boy runs 200 metres in 72 seconds. What is his speed ?
Options:
(A) 10 km/hr
(B) 14 km/hr
(C) 20 km/hr
(D) 12 km/hr
(E) 24 km/hr
Reasoning: 999 greater than 99.
Ans: (D)
Question: Which is greater than 99?
Options:
(A) 9
(B) 99
(C) 9.9
(D) 999
(E) 909
Reasoning: Hint: y^2-5 (y is an integer) is never multiple of 3 (try to prove this), hence 30 is out.
Ans: (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