question: 10 books are placed at random in a shelf. The probability that a pair of books will always be together is ?
Options:
(A) 1/8
(B) 1/4
(C) 1/5
(D) 1/9
(E) 1/1
answer: Stream of consciousness: 10 books can be rearranged in 10! ways consider the two books taken as a pair then number of favourable ways of getting these two books together is 9! 2!
Required probability = 1/5 The answer is (C).


q: A can do a job in 12 days and B can do it in 20 days. A and B working together will finish twice the amount of work in days?
Options:
(A) 22 1/6
(B) 22 1/2
(C) 22 1/0
(D) 15
(E) 22 1/1
a: Stream of consciousness: 1/12 + 1/20 = 8/60 = 2/15
15/2 = 15/2 *2 = 15 days The answer is (D).


question: If n is the greatest positive integer for which 4^n is a factor of 8!, then n =?
Options:
(A) 2
(B) 4
(C) 6
(D) 8
(E) 10
answer: Stream of consciousness: 8! = 40320
E. 4^10 = 1048576 (40320/1048576) - this is not a factor of 8!
D. 4^8 = 65536 (40320/65536) - this is not a factor of 8!
C. 4^6 = 4096 (40320/4096) - this is not a factor of 8!
B. 4^4 = 256 (40320/256) - this is not a factor of 8!
A. 4^2 = 16 (40320/16) - this is a factor of 8! The answer is (A).


q: There are 3 teams each with 7 basket players. How many combinations are there if we were to pick 2 players from the 3 teams such that no team was picked twice?
Options:
(A) 50
(B) 23
(C) 147
(D) 28
(E) 45
a: Stream of consciousness: There are altogether three arrangements, which are we can select two members each from team A and B, each from team A and C, and each from team B and C. For each arrangement, there are altogether 49 possibilities (7*7) since each team has 7 players. So there are a total of 147 possibilities (49*3). I hope this method is easier for you to understand. The answer is (C).


question: Let us say that a table tennis tournament was going on with knock out terms which means the one who loses the match is out of the tournament. 101 players took part in that tournament. How many matches were played?
Options:
(A) 90 matches
(B) 95 matches
(C) 99 matches
(D) 100 matches
(E) 87 matches
answer: Stream of consciousness: D
100 matches. The number of matches will always sum up to one less than the number of players in a knock out tournament. You may calculate it in any manner. Thus 100 matches were playe The answer is (D).


question: Q is a set of nine distinct prime numbers. If the sum of the integers in Q is even and the number x is a member of Q, then what is the least value that x can be?
Options:
(A) 2
(B) 3
(C) 4
(D) 5
(E) 7
answer:

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
Stream of consciousness: 2 + 3 + 5 + 7 +11 + 13 + 17 + 23 + 29 = 100 ( sum is even)
Least number = 2 The answer is (A).