Rationale: D = 72 * 5/18 = 20 = 400 â€“ 250 = 150m
The answer: (A)
Question: A train 250 m long running at 72 kmph crosses a platform in 20 sec. What is the length of the platform?
Options:
(A) 150m
(B) 200m
(C) 250m
(D) 270m
(E) 300 m

Reasoning: 20000(11/10)4 - 20000(6/5)2 = 482
Ans: (A)
Question: How much more would Rs.20000 fetch, after two years, if it is put at 20% p.a. compound interest payable half yearly than if is put at 20% p.a. compound interest payable yearly?
Options:
(A) Rs.482
(B) Rs.424
(C) Rs.842
(D) Rs.512
(E) Rs.524

Rationale: A's 1 day work = 1/10; B's 1 day work = 1/15
(A + B)'s 1 day work = (1/10 + 1/15) = 1/6
So, both together will finish the work in 6 days.
The answer: (B)
Question: A does a work in 10 days and B does the same work in 15 days. In how many days they together will do the same work?
Options:
(A) 1
(B) 6
(C) 7
(D) 5
(E) 43

Reasoning: D = 56 * 5/18 = 25 = 280 – 90 = 190
Ans: (A)
Question: A train 90 m long running at 56 kmph crosses a platform in 18 sec. What is the length of the platform?
Options:
(A) 190
(B) 200
(C) 180
(D) 881
(E) 271

Rationale: 7 * 156 â€“ 6 * 169 = 78
The answer: (D)
Question: The average of seven results is 156 and that of the first six is 169. The fifth result is?
Options:
(A) 120
(B) 160
(C) 89
(D) 78
(E) 148

Rationale: The total of seven numbers = 7X26 = 182
The total of first 3 and last 3 numbers is = 3 X 14+3 X 19 = 99
So, the middle number is (182 - 99 ) = 83
The answer: (B)

Question: The average of seven numbers is 26. The average of first three numbers is 14 and the average of last three numbers is 19. What is the middle number?
Options:
(A) 25
(B) 83
(C) 29
(D) 32
(E) 34