q: Two pipes can fill a tank in 20 and 12 hours, while third pipe will make the tank empty in 20 hours. If all three pipes operate simultaneously. In how many hours the tank will be filled ?
Options:
(A) 5 Hours
(B) 7 Hours
(C) 8 Hours
(D) 9 Hours
(E) 12 Hours
a: Stream of consciousness: In 1 hour it fill 1/20 + 1/12 - 1/20 = 1/12
So fill tank fill up in 12 Hours The answer is (E).

question: P and Q invested in a shop. The profits were divided in the ratio of 2 : 4 respectively. If P invested Rs. 500000, the amount invested by Q is:
Options:
(A) 5000000
(B) 4000000
(C) 1000000
(D) 6000000
(E) None
answer: Stream of consciousness: Suppose Q invested Rs. y. Then, 500000/y = 2/4 or y = [500000 x 4 / 2] = 1000000. The answer is (C).

q: If a train, travelling at a speed of 90 kmph, crosses a pole in 5 sec, then the length of train is?
Options:
(A) 288
(B) 125
(C) 88
(D) 76
(E) 232
a: Stream of consciousness: D = 90 * 5/18 * 5 = 125 m The answer is (B).

question: A train running at the speed of 60 km/hr crosses a pole in 6 sec. What is the length of the train?
Options:
(A) 120 m
(B) 100 m
(C) 324 m
(D) Cannot be determined
(E) None of these
answer: Stream of consciousness: Speed = 60* 5/18 = 50/3 m/sec
Length of the train = speed * time = 50/3 * 6 = 100 m The answer is (B).

q: A train running at the speed of 60 km/hr crosses a pole in 12 sec. What is the length of the train?
Options:
(A) 118
(B) 150
(C) 277
(D) 200
(E) 191
a: Stream of consciousness: Speed = 60 * 5/18 = 50/3 m/sec
Length of the train = speed * time = 50/3 * 12 = 200 m The answer is (D).

q: If 23m n = p, then which of the following represents the average (arithmetic mean) of m, n, and p, in terms of m?
Options:
(A) 2m 1
(B) 4m
(C) 6m
(D) m/5
(E) 8m
a:
Stream of consciousness: 23m - n = p
Add n to both sides:
23m = n + p
Add m to both sides:
24m = n + p + m
Now, divide both sides by 3
8m = (n + p + m)/3 = the average of n, p, and m The answer is (E).