q: A pipe can fill a cistern in 14 minutes whereas the cistern when fill can be emptied by a leak in 28 minutes. When both pipes are opened, find when the cistern will be full?
Options:
(A) 17
(B) 16
(C) 28
(D) 13
(E) 12
a: Stream of consciousness: 1/14 - 1/28 = 1/28
28 minutes The answer is (C).


question: Express 30 mps in kmph?
Options:
(A) 122
(B) 108
(C) 110
(D) 150
(E) 100
answer: Stream of consciousness: 30 * 18/5 = 108 kmph The answer is (B).


q: The edge of a cube is 9a cm. Find its surface?
Options:
(A) 153a2 cm2
(B) 143a2 cm2
(C) 233a2 cm2
(D) 243a2 cm2
(E) 253a2 cm2
a: Stream of consciousness: 6a2 = 6 * 9a * 9a = 243a2 The answer is (D).


question: 30 pens and 75 pencils were purchased for 630. If the average price of a pencil was 2.00, find the average price of a pen.
Options:
(A) 10
(B) 11
(C) 12
(D) 13
(E) 16
answer: Stream of consciousness: Since average price of a pencil = 2
∴ Price of 75 pencils = 150
∴ Price of 30 pens = (630 – 150) = 480
∴ Average price of a pen = 480⁄60 = 16 The answer is (E).


q: A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that atleast one bulb is good.
Options:
(A) 6/63
(B) 2/63
(C) 125/126
(D) 1/126
(E) 1/63
a: Stream of consciousness: Required probability = 1 - 1/126 = 125/126 The answer is (C).


q: A car traveled from San Diego to San Francisco at an average speed of 48 miles per hour. If the journey back took twice as long, what was the average speed of the trip?
Options:
(A) 24.
(B) 32.
(C) 36
(D) 42.
(E) 44.
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.
user
Stream of consciousness: Let the time taken be = x
One way distance = 48x
Total distance traveled = 2 * 48x = 96x
Total time taken = x + 2x = 3x
Average speed = 96x/3x = 32 The answer is (B).