10 books are placed at random in a shelf. The probability that a pair of books will always be together is
Options:
(A) 1/6
(B) 1/9
(C) 1/5
(D) 1/6
(E) 1/3
--
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 So the answer is: (C).
-----
If in a certain sequence of consecutive multiples of 100, the median is 650, and the greatest term is 1000, how many terms that are smaller than 650 are there in the sequence?
Options:
(A) 6
(B) 4
(C) 8
(D) 12
(E) 13
--
Since the median is 650 we know there must be a even number of integers
So the list around 625 must go. 600 ( 650) 700 800 900 1000
Since we know there are 4 numbers greater than 650 then there must be 4 numbers less then 650. So the answer is: (B).
-----
What approximate value should come in place of question mark (?) in the following equation
287.532 + 1894.029 – 657.48 = 743.095 + ?
Options:
(A) 870
(B) 790
(C) 780
(D) 770
(E) 890
--

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
? = 285 + 1895 – 655 – 745 or, ? = 780 So the answer is: (C).
-----