q: The average of 10 numbers is calculated as 15. It is discovered later on that while calculating the average, one number namely 36 was wrongly read as 26. The correct average is?
Options:
(A) 22
(B) 88
(C) 16
(D) 83
(E) 82
a: Stream of consciousness: 10 * 15 + 36 26 = 160/10 = 16 The answer is (C).

question: A 600 meter long train crosses a signal post in 40 seconds. How long will it take to cross a 3 kilometer long bridge, at the same speed?
Options:
(A) 4 min
(B) 2 min
(C) 8 min
(D) 9 min
(E) 5 min
answer: Stream of consciousness: S = 600/40 = 15 mps
S = 3600/15 = 240 sec = 4 min The answer is (A).

q: A train 560 m in length crosses a telegraph post in 16 seconds. The speed of the train is?
Options:
(A) 126 kmph
(B) 77 kmph
(C) 54 kmph
(D) 71 kmph
(E) 88 kmph
a: Stream of consciousness: S = 560/16 * 18/5 = 126 kmph The answer is (A).

question: Find the invalid no.from the following series 13, 18, 25, 30, 37, 40
Options:
(A) 13
(B) 18
(C) 40
(D) 37
(E) 40
answer: Stream of consciousness: The differences between two successive terms from the beginning are 7, 5, 7, 5, 7, 5. So, 40 is wrong. The answer is (C).

q: 30 pens and 75 pencils were purchased for 450. 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) 14
a: Stream of consciousness: Since average price of a pencil = 2
Price of 75 pencils = 150
Price of 30 pens = (450 150) = 300
Average price of a pen = 36060 = 10 The answer is (A).

q: If 1/2 of the air in a tank is removed with each stroke of a vacuum pump, what fraction of the original amount of air has been removed after 1 strokes ?
Options:
(A) 1/2
(B) 7/8
(C) 1/4
(D) 1/8
(E) 1/16
a:
Stream of consciousness: Left After 1st stroke = 1/2
So removed = 1- 1/2 = 1/2 The answer is (A).