Q: There are 9 fictions and 6 non-fictions. How many cases are there such that 2 fictions and 2 non-fictions are selected from them?
Options:
(A) 90
(B) 120
(C) 540
(D) 180
(E) 200
A: OK... Stream of consciousness: Number of ways of selecting 2 fiction books = 9C2
Number of ways of selecting 2 non fiction books = 6C2
9C2 * 6C2 = 36 * 15 = 540
The answer is (C).

Q: The simple interest on a sum of money is 4/9 of the principal and the number of years is equal to the rate percent. Find the rate and the time?
Options:
(A) 6 2/3%
(B) 6 2/9%
(C) 6 3/3%
(D) 9 2/3%
(E) 7 2/3%
A: OK... Stream of consciousness: 4/9 P = (P*R*R)/100
R = 20/3 = 6 2/3%
The answer is (A).

Q: Two numbers are in the ratio 3 : 4. If the sum of numbers is 63, find the numbers.
Options:
(A) 26,37
(B) 25,38
(C) 27,36
(D) 28,35
(E) 29,34
A: OK... Stream of consciousness: Sum of the terms of the ratio = 3 + 4 = 7
Sum of numbers = 63
Therefore, first number = 3/7 × 63 = 27
Second number = 4/7 × 63 = 36
Therefore, the two numbers are 27 and 36.
The answer is (C).

Q: How much is 25% of 40 is greater than 4/5 of 25?
Options:
(A) 10
(B) 776
(C) 66
(D) 12
(E) 99
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
OK... Stream of consciousness: (25/100) * 40 – (4/5) * 25
10 - 20 = 10
The answer is (A).