Reasoning: Part filled by (A + B + C) in 3 minutes = 3(1/30 + 1/20 + 1/10) = 11/20
Part filled by C in 3 minutes = 3/10
Required ratio = 3/10 * 20/11 = 6/11
Ans: (B)
Question: Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes and 10 minutes respectively. When the tank is empty, all the three pipes are opened. A, B and C discharge chemical solutions P, Q and R respectively. What is the proportion of solution R in the liquid in the tank after 3 minutes?
Options:
(A) 6/17
(B) 6/11
(C) 6/18
(D) 6/19
(E) 6/10
Rationale: 20 large cakes will require the equivalent of 10 helpers working for one hour. 700 small cakes will require the equivalent of 20 helpers working for one hour. This means if only one hour were available we would need 30 helpers. But since three hours are available we can use 10 helpers.
The answer: (B)
Question: Assisants are needed to prepare for preparation. Each helper can make either 2 large cakes or 35 small cakes/hour. The kitchen is available for 3hours and 20 large cakes and 700small cakes are needed. How many helpers are required?
Options:
(A) 9
(B) 10
(C) 13
(D) 16
(E) 18
Reasoning: Speed = 45 * 5/18 = 25/2 m/sec
Total distance covered = 360 + 140 = 750 m
Required time = 750 * 2/25 = 40 sec
Ans: (B)
Question: A train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 390 m long?
Options:
(A) 40 sec
(B) 60 sec
(C) 45 sec
(D) 48 sec
(E) 50 sec
Rationale: 12 men 120 acres 16 days
36 men ? 32 days
120 * 36/12 * 32/16
120 * 3 * 2
120 * 6 = 720
The answer: (D)
Question: If 12 men can reap 120 acres of land in 16 days, how many acres of land can 36 men reap in 32 days?
Options:
(A) 269
(B) 512
(C) 369
(D) 720
(E) 450
Reasoning: (80/100) * 40 – (10/100) * 15
32 - 15 = 17
Ans: (E)
Question: How much 80% of 40 is greater than 10% of 15?
Options:
(A) 18
(B) 99
(C) 19
(D) 18
(E) 17
Reasoning: 16⁄25P = P×R×R/100
⇒ R2 = 1600⁄25 ⇒ R = 40⁄5 = 8%
Also, time = 8 years
Ans: (A)

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.
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Question: Simple interest on a certain sum is 16 over 25 of the sum. Find the rate per cent and time, if both are equal.
Options:
(A) 8% and 8 years
(B) 6% and 6 years
(C) 10% and 10 years
(D) 12 % and 12 years
(E) None of these