(Ans). (C)
(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) 1/2
(C) 1/5
(D) 1/5
(E) 1/3
(CoT). 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

(Ans). (D)
(Question). The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero?
Options:
(A) 22
(B) 28
(C) 29
(D) 20
(E) 21
(CoT). Average of 20 numbers = 0
Sum of 20 numbers = (0 * 20) = 0
It is quite possible that 19 of these numbers may be positive and if their sum is a, then 20th number is (-a).

(Ans). (B)
(Question). If J is the least positive integer that is divisible by every integer from 10 to 15 inclusive, then J/26 is =
Options:
(A) 1155
(B) 2310
(C) 4620
(D) 30030
(E) 60060
(CoT). The integer should be divisible by: 10, 11, 12, 13, 14 and 15, that is 5*2, 11, 3*2^2, 13, 2*7, and 3*5. The least common multiple of these integers is the product of 13, 11, 7, 5, 3 and 2^2. Then, R/26 is (13 * 11 * 7 * 5 * 3 * 2^2)/2 * 13 = 11*7*5*3*2 = 2310.

(Ans). (B)
(Question).
Jerry covers a distance of 8km in 50 minutes. If he covers 3km distance in 2/5th of time then, What speed should he maintain to cover the remaining distance in the remaining time?
Options:
(A) 29 Kmph
(B) 15 Kmph
(C) 23 Kmph
(D) 22 Kmph
(E) 19 Kmph
(CoT). Total distance = 8 Km
Total time = 50 Km
Time taken to cover the distance of 3 Km = 50*2/5 = 20 min = 1/3 hours
Remaining distance = 8 - 3 = 5 Km
Required speed = 5/1/3 = 15 Kmph