The average of 11 results is 53, if the average of first six results is 49 and that of the last six is 52. Find the sixth result?
Options:
(A) A) 46
(B) B) 23
(C) C) 66
(D) D) 76
(E) E) 74

1 to 11 = 11 * 53 = 583
1 to 6 = 6 * 49 = 294
6 to 11 = 6 * 52 = 312
6th = 294 + 312 – 583 = 23 So the answer is: (B).

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%

{Total} = {finance} + {marketing} - {both} + {neither}
100 = 25 + 55 - {both} + 40
{both} = 20%. So the answer is: (D).

A and B can do a work in 5 days and 10 days respectively. A starts the work and B joins him after 2 days. In how many days can they complete the remaining work?
Options:
(A) 6
(B) 2
(C) 3
(D) 4
(E) 98

Work done by A in 2 days = 2/5
Remaining work = 3/5
Work done by both A and B in one day = 1/5 + 1/10 = 3/10
Remaining work = 3/5 * 10/3 = 2 day So the answer is: (B).

Two pipes can fill a tank in 30 and 12 hours, while third pipe will make the tank empty in 20 hours. If all three pipes operate simultaneously. In how many hours the tank will be filled ?
Options:
(A) 5 Hours
(B) 7 Hours
(C) 8 Hours
(D) 9 Hours
(E) 15 Hours

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
In 1 hour it fill 1/30 + 1/12 - 1/20 = 1/15
So fill tank fill up in 15 Hours So the answer is: (E).