Rationale: 10^2 - 20 = 80
20^2 - 30 = 370
30^2 - 40 = 860
40^2 - 50 = 1550
50^2 - 60 = 2440
60^2 - 70 = 3530.
The answer: (B)
Question: 80 370 860 1550 ? 3530
Options:
(A) 900
(B) 2440
(C) 750
(D) 244
(E) 960
Reasoning: S = (100 + 300)/45 = 400/45 * 18/5 = 32 kmph
Ans: (B)
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) 25 kmph
(B) 32 kmph
(C) 40 kmph
(D) 38 kmph
(E) 92 kmph
Rationale: 8/15 + 6/x = 1
X = 12 6/7days
The answer: (B)
Question: A can do a piece of work in 15 days. When he had worked for 2 days B joins him. If the complete work was finished in 8 days. In how many days B alone can finish the work?
Options:
(A) 11 6/7days
(B) 12 6/7days
(C) 13 6/7days
(D) 14 6/7days
(E) 15 6/7days
Reasoning: 252 = 2 x 2 x 3 x 3 x 7.
Ans: (A)
Question: 252 can be expressed as a product of primes as:
Options:
(A) 2 x 2 x 3 x 3 x 7
(B) 2 x 2 x 2 x 3 x 7
(C) 3 x 3 x 3 x 3 x 7
(D) 2 x 3 x 3 x 3 x 7
(E) 7 x 3 x 3 x 3 x 7
Rationale: 35 * 18/5 = 126 kmph
The answer: (C)
Question: Express 35 mps in kmph?
Options:
(A) 122
(B) 188
(C) 126
(D) 140
(E) 124
Rationale: Speed downstream = 60 + 10 = 70 kmph
Speed upstream = 60 - 10 = 50 kmph
The answer: (B)
Question: The speed of a boat in still water is 60kmph and the speed of the current is 10kmph. Find the speed downstream and upstream?
Options:
(A) 40, 68 kmph
(B) 70, 50 kmph
(C) 90, 60 kmph
(D) 40, 60 kmph
(E) 20, 60 kmph