Question: 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 4 days?
Options:
(A) 2/5
(B) 1/6
(C) 1/4
(D) 1/9
(E) 2/9
Answer: 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 4 days = 4 (1/18) = 2/9.
The answer is (E).

Question: How much is 80% of 45 is greater than 4/5 of 25?
Options:
(A) 15
(B) 57
(C) 16
(D) 16
(E) 73
Answer: (80/100) * 45 (4/5) * 25
36 - 20 = 16
The answer is (C).

Question: The average of first six prime numbers greater than 20 is?
Options:
(A) 10
(B) 20
(C) 30
(D) 40
(E) 34
Answer: 23 + 29 + 31 + 37 + 41 + 43 = 204/6 = 34
The answer is (E).

Question: A can do a piece of work in 10 days. He works at it for 4 days and then B finishes it in 9 days. In how many days can A and B together finish the work?
Options:
(A) 6
(B) 8
(C) 12
(D) 15
(E) 20
Answer:
4/10+9/X = 1/x = 15
1/10+1/15 = 1/6 = 6 days
The answer is (A).