q: 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
a: Stream of consciousness: 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: The average age of a family of 6 members is 26 years.If the age of the youngest member is 10 years,what was the average age of the family at the birth of the youngest member?
Options:
(A) 15
(B) 18
(C) 16
(D) 12
(E) 19
answer: Stream of consciousness: Present age of total members = 6 X 26 = 156
10 yrs back their ages were = 6 x 10 = 60
Ages at the birth of youngest member = 156 - 60 = 96
Therefore, avg age at the birth of youngest member = 96/6 = 16. The answer is (C).

q: Find the value of y from (12)^3 x 6^ 4 432 = y?
Options:
(A) 3456
(B) 4567
(C) 4789
(D) 5678
(E) y=5184
a: Stream of consciousness: Given Exp. = (12)3 x 64 = (12)3 x 64 = (12)2 x 62 = (72) 2 = 5184
432 12 x 62 The answer is (E).

question: There are 10 female and 15 male in a work place. In how many ways can a person can be selected?
Options:
(A) 20
(B) 15
(C) 18
(D) 40
(E) 25
answer: Stream of consciousness: No of ways = 10+ 15 = 25 The answer is (E).

q: How many cubes will have 4 coloured sides and two non-coloured sides ?
Options:
(A) 5
(B) 4
(C) 3
(D) 2
(E) 1
a: Stream of consciousness: Only 4 cubes situated at the corners of the cuboid will have 4 coloured and 2 non-coloured sides. The answer is (B).

q: A, B, C together started a business. A invested Rs.6000 for 5 months B invested Rs.3600 for 6 months and C Rs.7500 for 3 months. If they get a total profit of Rs.7410. Find the share of A?
Options:
(A) 3002
(B) 3000
(C) 3018
(D) 3019
(E) 3012
a:
Stream of consciousness: 60*5:36*6:75*3
100: 72: 75
100/247 * 7410 = 3000 The answer is (B).