An analyst will recommend a combination of 4 industrial stocks, 2 transportation stocks, and 2 utility stocks. If the analyst can choose from 5 industrial stocks, 4 transportation stocks, and 3 utility stocks, how many different combinations of 8 stocks are possible?
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Options:
(A) 12
(B) 19
(C) 90
(D) 180
(E) 720

5C4 * 4C2 * 3C2 = 5*6*3 = 90. So the answer is: (C).

In what time will a railway train 40 m long moving at the rate of 36 kmph pass a telegraph post on its way?
Options:
(A) 3 sec
(B) 4 sec
(C) 5 sec
(D) 6 sec
(E) 7 sec

T = 40/36 * 18/5 = 4 sec So the answer is: (B).

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 2 strokes ?
Options:
(A) 3/4
(B) 7/8
(C) 1/4
(D) 1/8
(E) 1/16

Left After 1st stroke = 1/2
Left After 2nd stroke = 1/2 * 1/2 = 1/4
So removed = 1- 1/4 = 3/4 So the answer is: (A).

Find a a prime number from the options below.
Options:
(A) 37
(B) 38
(C) 39
(D) 40
(E) 42

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
Clearly, 37 is a prime number. So the answer is: (A).