q: Ravi can do a piece of work in 30 days while Prakash can do it in 40 days. In how many days will they finish it together?
Options:
(A) 19 1/7 days
(B) 16 1/7 days
(C) 14 1/7 days
(D) 17 1/7 days
(E) 13 1/7 days
a: Stream of consciousness: 1/30 + 1/40 = 7/120
120/7 = 17 1/7 days The answer is (D).

question: A train 150 meters long completely crosses a 240 meters long bridge in 42 seconds. What is the speed of the train is?
Options:
(A) 32
(B) 33
(C) 88
(D) 66
(E) 09
answer: Stream of consciousness: S = (150 + 240)/42 = 390/42 * 18/5 = 33 The answer is (B).

q: A box contains nine bulbs out of which 4 are defective. If four bulbs are chosen at random, find the probability that atleast one bulb is good.
Options:
(A) 125/127
(B) 127/125
(C) 125/126
(D) 126/125
(E) 126/127
a: Stream of consciousness: Required probability = 1 - 1/126 = 125/126 The answer is (C).

question: From the set of numbers x, y, t, z, p, q and w, how many different combinations can we have without the t and w in them? Ex:. (x,y), (x), (p,q,z,y,x), etc and (x,y)=(y,x)
Options:
(A) 10
(B) 14
(C) 15
(D) 16
(E) 30
answer: Stream of consciousness: Another way: Any letter (x, y, z, p, q) can be included or not. So, we have 2^5 combinations - 2 empty combinations = 30 combinations The answer is (E).

q: From the set of numbers x, y, t, z, p, q, r and w, how many different combinations can we have without the t,p,q and r in them? Ex:. (x,y), (x), (w,z,y,x), etc and (x,y)=(y,x)
Options:
(A) 10
(B) 12
(C) 15
(D) 16
(E) 30
a: Stream of consciousness: Another way: Any letter (x, y, z, w) can be included or not. So, we have 2^4 combinations - 4 empty combination = 12 combinations The answer is (B).

q: Is 2 a prime number or a composite number?
Options:
(A) prime number
(B) composite number
(C) both prime composite number
(D) Not prime composite number
(E) Don't Know
a:
Stream of consciousness: A Prime Number can be divided evenly only by 1 or itself
So 2 is prime number The answer is (A).