q: Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 6 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) 240 gallons
(D) 180 gallons
(E) 130 gallons
a: 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 = 6 gallonsVolume of whole = 6 * 40 = 240 gallons. The answer is (C).

question: 1,2,2,4,8,32,?(mult)
Options:
(A) 2816
(B) 1816
(C) 2812
(D) 2817
(E) 6816
answer: Stream of consciousness: Each number is the product of the previous two numbers, ie 8*32 = 2816. The answer is (A).

q: It is the New Year and Mandy has made a resolution to lose weight this year. She plans to exercise and do yoga. For exercise she plans to workout at the gym and ride her bicycle in the ratio of 2:3 everyday. She will also do yoga in the ratio, yoga:exercise = 2:3. If she rides her bike for 20 minutes, how much time will she spend doing yoga? (rounded to minutes)
Options:
(A) 10 min.
(B) 33 min.
(C) 17 min.
(D) 23 min.
(E) 25 min.
a: Stream of consciousness: The ratio is 2:3 = gym:ride, so (20)(3/2) = 30 minutes at the gym, and 30 + 20 = 50 minutes exercise, so (2/3)(50) = 33 minutes yoga. The answer is (B).

question: If 85 percent of the test takers taking an old paper and pencil GMAT exam answered the first question on a given math section correctly, and 75 percent of the test takers answered the second question correctly, and 15 percent of the test takers answered neither question correctly, what percent answered both correctly?
Options:
(A) 60 %
(B) 65 %
(C) 70%
(D) 75%
(E) 80%
answer: Stream of consciousness: {Total} = {First correctly} + {Second correctly} - {Both correctly} + {Neither correctly}
100 = 85 + 75 - {Both correctly} + 15
{Both correctly} = 75. The answer is (D).

q: Rs. 1300 is divided into three parts A, B and C. How much A is more than C if their ratio is 1/2:1/3:1/4?
Options:
(A) 297
(B) 268
(C) 300
(D) 179
(E) 172
a: Stream of consciousness: 1/2:1/3:1/4 = 6:4:3
3/13*1300 = 300 The answer is (C).

q: In a school of 850 boys, 44% of Muslims, 28% Hindus, 10% Sikhs and the remaining of other communities. How many belonged to the other communities?
Options:
(A) 277
(B) 267
(C) 153
(D) 188
(E) 151
a:
Stream of consciousness: 44 + 28 + 10 = 82%
100 82 = 18%
850 * 18/100 = 153 The answer is (C).