Reasoning: Let the boys are X, then girls are 7X, total = X+7X = 8X
So it should be multiple of 8, 30 is not a multiple of 8.
Ans: (C)
Question: The no. of girls in a class are seven times the no. of boys, which value cannever be the of total students?
Options:
(A) 23
(B) 25
(C) 30
(D) 36
(E) 39
Rationale: Clearly, 252 = 2 x 2 x 3 x 3 x 7.
The answer: (A)
Question: 252 can be expressed as a product of primes as:
Options:
(A) 2 x 2 x 3 x 3 x 7
(B) 2 x 2 x 3 x 3 x 8
(C) 2 x 2 x 3 x 3 x 6
(D) 2 x 2 x 3 x 3 x 1
(E) 2 x 2 x 3 x 3 x 2
Reasoning: (10/108)/(5/20) = 20/27 = 74% it means that 10/108 represents only 74%. Therefore a decrease of 26%.
Ans: (B)
Question: A pharmaceutical company received $5 million in royalties on the first $20 million in sales of and then $10 million in royalties on the next $108 million in sales. By approximately what percentage did the ratio of royalties to sales decrease from the first $20 million in sales to the next $108 million in sales?
Options:
(A) 8%
(B) 26%
(C) 45%
(D) 52%
(E) 56%
Rationale: The total of seven numbers = 7X18 = 126
The total of first 3 and last 3 numbers is = 3 X 14+3 X 19 = 99
So, the middle number is (126 - 99 ) = 27
The answer: (B)
Question: The average of seven numbers is 18. The average of first three numbers is 14 and the average of last three numbers is 19. What is the middle number?
Options:
(A) 25
(B) 27
(C) 29
(D) 32
(E) 34
Reasoning: D = 500 + 230 = 730
S = 44 * 5/18 = 12 mps
T = 730/12 = 61 sec
Ans: (D)
Question: A train 500 meters long is running with a speed of 44 kmph. The time taken by it to cross a tunnel 230 meters long is?
Options:
(A) 287 sec
(B) 288 sec
(C) 48 sec
(D) 61 sec
(E) 17 sec
Reasoning: ? = 285 + 1895 655 645 or, ? = 880
Ans: (C)
Question: What approximate value should come in place of question mark (?) in the following equation
287.532 + 1894.029 657.48 = 643.095 + ?
Options:
(A) 870
(B) 790
(C) 880
(D) 770
(E) 890