Question: Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is?
Options:
(A) 299
(B) 2767
(C) 120
(D) 287
(E) 261
Answer: Work done by the waste pipe in 1 minute = 1/15 - (1/20 + 1/24) = - 1/40
Volume of 1/40 part = 3 gallonsVolume of whole = 3 * 40 = 120 gallons.
The answer is (C).

Question: How much 60% of 50 is greater than 40% of 30?
Options:
(A) 18
(B) 55
(C) 33
(D) 22
(E) 11
Answer: (60/100) * 50 (40/100) * 30
30 - 12 = 18
The answer is (A).

Question: If Rs.7500 are borrowed at C.I at the rate of 4% per annum, then after 4 years the amount to be paid is?
Options:
(A) 3377
(B) 2688
(C) 2688
(D) 8774
(E) 1268
Answer: A = 7500(26/25)^4 = 8774
The answer is (D).

Question: A and B can do a work in 2 days, B and C in 6 days and C and A in 8 days. In how many days will the work be completed, if all three of them work together?
Options:
(A) 12/28
(B) 48/19
(C) 16/48
(D) 18/48
(E) 12/64
Answer:
One day work of A and B = 1/2
One day work of B and C = 1/6
One day work of C and A = 1/8
2(A + B + C) = 1/2 + 1/6 + 1/8
2(A + B + C) = 19/24
(A + B + C) = 19/48
Number of days required = 48/19 days.
The answer is (B).