If 12 men can reap 120 acres of land in 36 days, how many acres of land can 54 men reap in 54 days?
Options:
(A) 277
(B) 810
(C) 888
(D) 166
(E) 199

12 men 120 acres 36 days
54 men ? 54 days
120 * 54/12 * 54/36
10 * 54 * 3/2
54 * 15 = 810 So the answer is: (C).

If 1/2 of the air in a tank is removed with each stroke of a vacuum pump, what fraction of the original amount of air has been removed after 2 strokes ?
Options:
(A) 3/4
(B) 7/8
(C) 1/4
(D) 1/8
(E) 1/16

Left After 1st stroke = 1/2
Left After 2nd stroke = 1/2 * 1/2 = 1/4
So removed = 1- 1/4 = 3/4 So the answer is: (A).

Find the value of y from (12)^3 x 6^4 ÷ 432 = y?
Options:
(A) 2134
(B) 2245
(C) 3450
(D) 4500
(E) 5184

Given Exp. = (12)3 x 64 = (12)3 x 64 = (12)2 x 62 = (72)2 = 5184
432 12 x 62 So the answer is: (E).

The average age of a class of 40 students is 15 yrs. if the teacher's age is also included, the average increases by one year. Find the age of the teacher
Options:
(A) 30 Years
(B) 56 Years
(C) 32 Years
(D) 34 Years
(E) 49 Years

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
Total age of students is 40X15 = 600 Years
Total age inclusive of teacher = 41X (15+1) = 656
So, Teacher's age is 656-600 = 56 Yrs
There is a shortcut for these type of problems
Teacher's age is 15+(41X1) = 56 Years So the answer is: (B).