Question: The average age of P, Q, R, S five years ago was 45 years. By including T, the present average age of all the five is 49 years. The present age of T is?
Options:
(A) 64 years
(B) 48 years
(C) 45 years
(D) 40 years
(E) None of these
Answer: Present age of P, Q, R, S = 45 x 4 + 20 = 200
Present age of P, Q, R, S and T = 49 x 5 = 245
Hence, the age of T = 245 - 200 = 45 years.
The answer is (C).

Question: A man rows his boat 78 km downstream and 56 km upstream, taking 4 hours each time. Find the speed of the stream?
Options:
(A) 6
(B) 5
(C) 7
(D) 8
(E) 3
Answer: Speed downstream = d/t = 78/(4) = 20 kmph
Speed upstream = d/t = 56/(4) = 14 kmph
The speed of the stream = (20 - 14)/2 = 3 kmph
The answer is (E).

Question: Twenty percent of Country Y's yearly exports come from fruit exports. One-fourth of all fruit exports from Country Y are orange exports. If country Y generates $20 million from its orange exports, how much money does it generate from its yearly total of exports?
Options:
(A) $21.25m
(B) $25.5m
(C) $106.25m
(D) $400m
(E) $153m
Answer: 20/100*1/4*(total) = 20
1/20*(total) = 20
(total) = 20*20 = 400
The answer is (D).

Question: The edge of a cube is 3a cm. Find its surface?
Options:
(A) 64a2 cm2
(B) 54a2 cm2
(C) 84a2 cm2
(D) 24a2 cm2
(E) 34a2 cm2
Answer:
6a2 = 6 * 3a * 3a = 54a2
The answer is (B).