Question: Walking across campus, a student interviewed a group of students. 25% of the students took a finance class last semester, 55% took a marketing class last semester, and 40% took neither a finance nor a marketing class last semester. What percent of the students in the group took both a finance and a marketing class?
Options:
(A) 60%
(B) 50%
(C) 25%
(D) 20%
(E) 10%
Answer: {Total} = {finance} + {marketing} - {both} + {neither}
100 = 25 + 55 - {both} + 40
{both} = 20%.
The answer is (D).

Question: Look at this series: 53, 53, 39, 39, 25, 25, ... What number should come next?
Options:
(A) A) 12
(B) B) 11
(C) C) 27
(D) D) 53
(E) E) 86
Answer: In this series, each number is repeated, then 14 is subtracted to arrive at the next number.
The answer is (B).

Question: You have a flashlight that takes 2 working batteries. You have 8 batteries but only 4 of them work.
What is the fewest number of pairs you need to test to guarantee you can get the flashlight on?
Options:
(A) 5
(B) 8
(C) 7
(D) 6
(E) 4
Answer: If you break the batteries into 3 groups: Two groups of 3 and one group of 2. By doing this you guarantee that one of the groups has 2 working batteries. Both of the groups of 3 have 3 possible combinations of 2 batteries and the group of 2 only has 1 combination. So, 3 + 3 + 1 = 7 tries at most to find two working batteries.
The answer is (C).

Question: A cricket bat is sold for $850, making a profit of $245. The profit percentage would be
Options:
(A) 24%
(B) 25%
(C) 30%
(D) 36%
(E) 40%
Answer:

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
245/(850 - 245) = 245/605 = 49/121 = 40%.
The answer is (E).