Question: A pharmaceutical company received $3 million in royalties on the first $30 million in sales of and then $9 million in royalties on the next $120 million in sales. By approximately what percentage did the ratio of royalties to sales decrease from the first $30 million in sales to the next $120 million in sales?
Options:
(A) 8%
(B) 15%
(C) 25%
(D) 52%
(E) 56%
Answer: (9/120)/(3/30) = 3/4 = 75% it means that 9/120 represents only 75%. Therefore a decrease of 25%.
The answer is (C).

Question: Solve below question 4x + 1 = 37
Options:
(A) -8
(B) -9
(C) -5
(D) 9
(E) 1
Answer: 1. Subtract 1 from both sides: 4x + 1 - 1 = 37 - 1 2. Simplify both sides: 4x = 36 3. Divide both sides by 4: 4. Simplify both sides: x = 9
The answer is (D).

Question: Find the average of the first 21 natural numbers?
Options:
(A) 8
(B) 9
(C) 10
(D) 11
(E) 12
Answer: Average of the first 'n' natural numbers = (n + 1)/2
We get (21+ 1)/2 = 11
The answer is (D).

Question: X can finish a work in 18 days. Y can finish the same work in 15 days. Yworked for 5 days and left the job. how many days does X alone need to finish the remaining work?
Options:
(A) 12
(B) 5
(C) 6
(D) 8
(E) 9
Answer:
Work done by X in 1 day = 1/18
Work done by Y in 1 day = 1/15
Work done by Y in 5 days = 5/15 = 1/3
Remaining work = 1 1/3 = 2/3
Number of days in which X can finish the remaining work = (2/3) / (1/18) = 12
The answer is (A).