q: Look at this series: 0.05, 0.2, ____, 3.2, 12.8, ... What number should fill the blank?
Options:
(A) 0.5
(B) 0.6
(C) 0.9
(D) 0.7
(E) 0.8
a: OK... This is a simple multiplication series. Each number is 4 times greater than the previous number.
The answer is (E).

q: An analyst will recommend a combination of 2 industrial stocks, 2 transportation stocks, and 1 utility stocks. If the analyst can choose from 6 industrial stocks, 5 transportation stocks, and 3 utility stocks, how many different combinations of 5 stocks are possible?
Options:
(A) 12
(B) 460
(C) 60
(D) 450
(E) 720
a: OK... 6C2 * 5C2 * 3C1 = 15*10*3 = 450.
The answer is (D).

q: A can do a piece of work in 4 hours; B and C together can do it in 3 hours, which A and C together can do it in 2 hours. How long will B alone take to do it?
Options:
(A) 15 hours
(B) 14 hours
(C) 12 hours
(D) 74 hours
(E) 79 hours
a:
OK... A's 1 hour work = 1/4;
(B + C)'s 1 hour work = 1/3;
(A + C)'s 1 hour work = 1/2
(A + B + C)'s 1 hour work = (1/4 + 1/3) = 7/12
B's 1 hour work = (7/12 + 1/2) = 1/12
B alone will take 12 hours to do the work.
The answer is (C).