[Ques]: The average of first 10 even numbers is?
Options:
(A) 19
(B) 18
(C) 16
(D) 11
(E) 17
*Ans*: (D)
--CoT--: Sum of 10 even numbers = 10 * 11 = 110
Average = 110/10 = 11

[Ques]: By travelling at 40 kmph, a person reaches his destination on time. He covered two-third the total distance in one-third of the total time. What speed should he maintain for the remaining distance to reach his destination on time?
Options:
(A) 20
(B) 99
(C) 88
(D) 77
(E) 61
*Ans*: (A)
--CoT--: Let the time taken to reach the destination be 3x hours. Total distance = 40 * 3x = 120x km
He covered 2/3 * 120x = 80x km in 1/3 * 3x = x hours So, the remaining 40x km, he has to cover in 2x hours. Required speed = 40x/2x = 20 kmph.

[Ques]: 10 books are placed at random in a shelf. The probability that a pair of books will always be together is
Options:
(A) 1/9
(B) 1/7
(C) 1/5
(D) 1/6
(E) 1/3
*Ans*: (C)
--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

[Ques]: If 85 percent of the test takers taking an old paper and pencil GMAT exam answered the first question on a given math section correctly, and 75 percent of the test takers answered the second question correctly, and 15 percent of the test takers answered neither question correctly, what percent answered both correctly?
Options:
(A) 60 %
(B) 65 %
(C) 70%
(D) 75%
(E) 80%
*Ans*: (D)
--CoT--: {Total} = {First correctly} + {Second correctly} - {Both correctly} + {Neither correctly}
100 = 85 + 75 - {Both correctly} + 15
{Both correctly} = 75.