Two persons A and B can complete a piece of work in 30 days and 45 days respectively. If they work together, what part of the work will be completed in 3 days?
Options:
(A) 1/8
(B) 1/3
(C) 1/6
(D) 1/2
(E) 5/3

A's one day's work = 1/30
B's one day's work = 1/45
(A + B)'s one day's work = 1/30 + 1/45 = 1/18
The part of the work completed in 3 days = 3 (1/18) = 1/6. So the answer is: (C).

John makes $40 a week from his job. He earns a raise and now makes $60 a week. What is the % increase?
Options:
(A) 16%
(B) 16.66%
(C) 18%
(D) 21%
(E) 50%

Increase = (20/40)*100 = 50%. So the answer is: (E).

Find the invalid no.from the following series 13, 18, 25, 30, 37, 40
Options:
(A) 13
(B) 18
(C) 40
(D) 37
(E) 25

The differences between two successive terms from the beginning are 7, 5, 7, 5, 7, 5. So, 40 is wrong. So the answer is: (C).

How much is 80% of 40 is greater than 4/5 of 25?
Options:
(A) 229
(B) 87
(C) 26
(D) 12
(E) 667
(80/100) * 40 (4/5) * 25
32 - 20 = 12 So the answer is: (D).