Calculate the speed of a boat in still water (in km/hr) if in one hour, the boat goes 15 km/hr downstream and 7 km/hr upstream.
Options:
(A) 12 kmph
(B) 13 kmph
(C) 14 kmph
(D) 15 kmph
(E) 11 kmph
Answer and stream of consciousness: (E)
Stream of consciousness: Speed in still water = (15 + 7)1/2 kmph = 11 kmph.

An analyst will recommend a combination of 3 industrial stocks, 2 transportation stocks, and 2 utility stocks. If the analyst can choose from 4 industrial stocks, 5 transportation stocks, and 3 utility stocks, how many different combinations of 7 stocks are possible?
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Options:
(A) 12
(B) 19
(C) 60
(D) 180
(E) 720
Answer and stream of consciousness: (E)
Stream of consciousness: 4C3 * 5C2 * 3C2 = 4*60*3 = 720.

What is the probability that Company R's advertisement will be one of the first two be shown during the first commercial break?
Options:
(A) 1/ 225
(B) 1 / 30
(C) 1 /15
(D) 2 / 15
(E) 4 /15
Answer and stream of consciousness: (D)
Stream of consciousness: R 1/15 + (14/15) * 1/14 = 2/15

A single discount equivalent to the discount series of 20%, 10% and 25% is?
Options:
(A) 31.9
(B) 31.7
(C) 31.6
(D) 31.5
(E) 46
Answer and stream of consciousness:
(E)
Stream of consciousness: 100*(80/100)*(90/100)*(75/100) = 54
100 - 54 = 46