question: One copy machine can make 20 copies a minute, and a second copy machine makes 10 copies a minute. If the two copiers work together, how long would it take them to make 900 copies?
Options:
(A) 10 minutes
(B) 20 minutes
(C) 25 minutes
(D) 30 minutes
(E) 35 minutes
answer: Stream of consciousness: Total work done by both machines in a minute = 20 + 10 = 30 copies
Total number of copies required = 900
Time = 900/30 = 30 mins The answer is (D).

q: Which of the following is equal to the average (arithmetic mean) of (x+2)^2 and (x-4)^2?
Options:
(A) x^2
(B) x^2+2
(C) x^2-2x+10
(D) x^2+2x+10
(E) x^2+4x+5
a: Stream of consciousness: Avg = [(x+2)^2 + (x-4)^2] / 2
Expanding and simplifying, (x^2 + 4x + 4 + x^2 - 8x + 16 ) / 2 = x^2 - 2x +10 The answer is (C).

question: In what time will a railway train 70 m long moving at the rate of 36 kmph pass a telegraph post on its way?
Options:
(A) 5 sec
(B) 4 sec
(C) 3 sec
(D) 7 sec
(E) 1 sec
answer: Stream of consciousness: T = 70/36 * 18/5 = 7 sec The answer is (D).

q: Find a a prime number from the options below.
Options:
(A) 37
(B) 38
(C) 39
(D) 40
(E) 42
a: Stream of consciousness: Clearly, 37 is a prime number. The answer is (A).

question: There are five same model cars parked in the same direction in parking. If 3 cars are red, 1 is black and 1 is green, in how many ways they can be arranged in the parking?
Options:
(A) 10 ways.
(B) 20 ways.
(C) 30 ways.
(D) 40 ways.
(E) 50 ways.
answer: Stream of consciousness: 5!/(3!*1!*1!) = (5*4*3*2*1)/(3*2*1) = 120/6 = 20 ways. The answer is (B).

question: There are 8 books in a shelf that consist of 1 paperback books and 7 hardback books. If 3 books are selected at random without replacement, how many different combinations are there that at least one paperback book is selected?
Options:
(A) 21
(B) 45
(C) 50
(D) 55
(E) 60
answer:
Stream of consciousness: 8C3 [Select any four] - 7C3 [Select all hard backs] = 21 The answer is (A).