Question: Find 96 98
Options:
(A) 92/8
(B) 92/12
(C) 92/13
(D) 92/10
(E) 92/11
Answer: Here both numbers are less than 100. So they are deficient of - 4 and - 2 compared with 100. So
The answer is (A).

Question: The average of 11 results is 50, if the average of first six results is 49 and that of the last six is 52. Find the sixth result?
Options:
(A) 46
(B) 56
(C) 66
(D) 76
(E) 74
Answer: 1 to 11 = 11 * 50 = 550
1 to 6 = 6 * 49 = 294
6 to 11 = 6 * 52 = 312
6th = 294 + 312 550 = 56
The answer is (B).

Question: The average of 13 numbers is 60. Average of the first 6 of them is 57 and that of the last 8 is 61. Find the 8th number?
Options:
(A) 46
(B) 48
(C) 50
(D) 52
(E) 54
Answer: Sum of all the 13 numbers = 13 * 60 = 780
Sum of the first 6 of them = 6 * 57 = 342
Sum of the last 8 of them = 8 * 61 = 488
So, the 8th number = 342 + 488 - 780 = 50.
The answer is (C).

Question: A man rows his boat 65 km downstream and 45 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?
Options:
(A) 5 kmph
(B) 4 kmph
(C) 9 kmph
(D) 8 kmph
(E) 1 kmph
Answer:
Speed downstream = d/t = 65/(2 1/2) = 26 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (26 - 18)/2 = 4 kmph
The answer is (B).