q: A can do a piece of work in 12 days. When he had worked for 2 days B joins him. If the complete work was finished in 8 days. In how many days B alone can finish the work?
Options:
(A) 18
(B) 77
(C) 66
(D) 55
(E) 12
a: Stream of consciousness: 8/12 + 6/x = 1
X = 18 days The answer is (A).

question: Two trains are traveling on parallel tracks in the same direction. The faster train travels at 130 miles per hour, while the slower train travels at 100 miles per hour. At 2 o'clock the faster train is 20 miles behind the slower one. How far apart are the two trains at 5 o'clock?
Options:
(A) 60 miles
(B) 70 miles
(C) 90 miles
(D) 120 miles
(E) 400 miles
answer: Stream of consciousness: Answer = B. 70 miles
Relational speed = 130 - 100 = 30 miles per hour
In 3 hours, difference = 30 * 3 = 90 miles
Fast train trailing 20 miles, so effective difference = 90 - 20 = 70 miles The answer is (B).

q: Out of 15 consecutive numbers, 2 are chosen at random. The probability that they are both odds or both primes is
Options:
(A) 10/17
(B) 10/19
(C) 46/105
(D) 11/15
(E) Cannot be determined
a: Stream of consciousness: There is no definite formula for finding prime numbers among 15 consecutive numbers. Hence the probability cannot be determined. The answer is (E).

question: Which one of the following is not a prime number?
Options:
(A) 2
(B) 3
(C) 5
(D) 9
(E) 7
answer: Stream of consciousness: 9 is divisible by 3. So, it is not a prime number. The answer is (D).

q: If x is an odd integer, which of the following is an odd integer?
Options:
(A) 2x
(B) 3x-1
(C) 5x+6
(D) x+x^2
(E) 6x-6
a: Stream of consciousness: Plug in an odd integer; in this case 3
(2*3) = 6 Even
(3*3)-1 = 8 Even
(5*3)+6 = 15 + 6 = 21 Odd
3+3^2 = 3 + 9 = 12 Even
(6*3)-6 = 18 - 6 = 12 Even The answer is (C).

q: If a train, travelling at a speed of 90 kmph, crosses a pole in 5 sec, then the length of train is?
Options:
(A) 288
(B) 125
(C) 88
(D) 76
(E) 232
a:
Stream of consciousness: D = 90 * 5/18 * 5 = 125 m The answer is (B).