question: Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 4 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is?
Options:
(A) 60 gallons
(B) 100 gallons
(C) 120 gallons
(D) 160 gallons
(E) 130 gallons
answer: Stream of consciousness: Work done by the waste pipe in 1 minute = 1/15 - (1/20 + 1/24) = - 1/40
Volume of 1/40 part = 4 gallonsVolume of whole = 4 * 40 = 160 gallons. The answer is (D).

q: Calculate the largest 3 digit number which is exactly divisible by 89?
Options:
(A) 911
(B) 969
(C) 979
(D) 977
(E) 971
a: Stream of consciousness: Largest 4 digit number is 999
After doing 999 89 we get remainder 20
Hence largest 3 digit number exactly divisible by 89 = 999 - 20 = 979 The answer is (C).

question: If 8m 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) 3m
(C) 6m
(D) m/5
(E) 6m/5
answer: Stream of consciousness: 8m - n = p
Add n to both sides:
8m = n + p
Add m to both sides:
9m = n + p + m
Now, divide both sides by 3
3m = (n + p + m)/3 = the average of n, p, and m The answer is (B).

q: The speed of a boat in upstream is 80 kmph and the speed of the boat downstream is 100 kmph. Find the speed of the boat in still water and the speed of the stream?
Options:
(A) 90, 10 kmph
(B) 35, 27 kmph
(C) 50, 60 kmph
(D) 45, 55 kmph
(E) 45, 65 kmph
a: Stream of consciousness: Speed of the boat in still water = (80+100)/2 = 90 kmph. Speed of the stream = (100-80)/2 = 10 kmph The answer is (A).

question: If the average (arithmetic mean) of the four numbers K, 2K + 3, 3K 5 and 5K + 1 is 96, what is the value of K?
Options:
(A) 11
(B) 15 3/4
(C) 22
(D) 35
(E) 25 3/10
answer: Stream of consciousness: K + 2K +3 + 3K - 5 + 5K +1 = 11K -1
(11K -1)/4 = 96
11K = 96 * 4 +1 = 384 +1 = 385
K = 385 / 11 = 35. The answer is (D).

question: The edge of a cube is 7a cm. Find its surface?
Options:
(A) 24a8
(B) 24a4
(C) 24a1
(D) 24a2
(E) 294a2
answer:
Stream of consciousness: 6a2 = 6 * 7a * 7a = 294a2 The answer is (E).