Q: Walking across campus, a student interviewed a group of students. 25% of the students took a finance class last semester, 50% 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) 15%
(E) 10%
A: OK... Stream of consciousness: {Total} = {finance} + {marketing} - {both} + {neither}
100 = 25 + 50 - {both} + 40
{both} = 15%.
The answer is (D).

Q: A train 120 m long running at 60 kmph crosses a platform in 35 sec. What is the length of the platform?
Options:
(A) 338
(B) 277
(C) 463
(D) 456
(E) 271
A: OK... Stream of consciousness: D = 60 * 5/18 = 35 = 583 – 120 = 463
The answer is (C).

Q: A women purchased 3 towels @ Rs.100 each, 5 towels @ Rs.150 each and two towels at a certain rate which is now slipped off from his memory. But she remembers that the average price of the towels was Rs.160. Find the unknown rate of two towels?
Options:
(A) A) 400
(B) B) 450
(C) C) 500
(D) D) 550
(E) E) 600
A: OK... Stream of consciousness: 10 * 160 = 1600
3 * 100 + 5 * 150 = 1050
1600 – 1050 = 550
The answer is (D).

Q: If 17m − n = p, then which of the following represents the average (arithmetic mean) of m, n, and p, in terms of m?
Options:
(A) 2m −1
(B) 4m
(C) 6m
(D) m/5
(E) 6m/5
A:

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
OK... Stream of consciousness: 17m - n = p
Add n to both sides:
17m = n + p
Add m to both sides:
18m = n + p + m
Now, divide both sides by 3
6m = (n + p + m)/3 = the average of n, p, and m
The answer is (C).