q: Anil can do a work in 15 days while Sunil can do it in 25 days. How long will they take if both work together?
Options:
(A) 3 4/9 days
(B) 8 4/9 days
(C) 9 3/8 days
(D) 6 3/8 days
(E) none of these
a: Stream of consciousness: 1/15 + 1/25 = 8/75
75/8 = 9 3/8 days The answer is (C).

question: Two trains are traveling on parallel tracks in the same direction. The faster train travels at 120 miles per hour, while the slower train travels at 100 miles per hour. At 2 o'clock the faster train is 10 miles behind the slower one. How far apart are the two trains at 6 o'clock?
Options:
(A) 60 miles
(B) 80 miles
(C) 110 miles
(D) 120 miles
(E) 400 miles
answer: Stream of consciousness: Answer = C. 110 miles
Relational speed = 120 - 100 = 20 miles per hour
In 4 hours, difference = 20 * 4 = 120 miles
Fast train trailing 10 miles, so effective difference = 120 - 10 = 110 miles The answer is (C).

q: There are 18 balls in a jar. You take out 3 black balls without putting them back inside, and now the probability of pulling out a black ball is 1/3. How many blue balls were there in the beginning?
Options:
(A) 12.
(B) 9.
(C) 8.
(D) 7.
(E) 6.
a: Stream of consciousness: 8 = 3 blue balls + 15 / 3 The answer is (C).

question: Consider a quarter of a circle of radius 20. Let r be the radius of the circle inscribed in this quarter of a circle. Find r.
Options:
(A) 20*(sqr2 -1)
(B) 8*(sqr3 -1)
(C) 4*(sqr7 - 1)
(D) 12* (sqr7 -1)
(E) None of these
answer: Stream of consciousness: I got 20/(sqr2 +1) and just forgot to multiply by (sqr2 -1). The answer is (A).

q: The average of seven results is 156 and that of the first six is 169. The fifth result is?
Options:
(A) 120
(B) 160
(C) 89
(D) 78
(E) 148
a: Stream of consciousness: 7 * 156 6 * 169 = 78 The answer is (D).

q: There are a total of 15 numbers with an average of 11. The average of first seven numbers is 14 and the average of last seven numbers is 6. What is the middle number?
Options:
(A) 31
(B) 24
(C) 29
(D) 25
(E) 21
a:
Stream of consciousness: The total of 15 numbers = 15X11 = 165
The total of first 7 and last 7 numbers is = 7 X 14+7 X 6 = 140
So, the middle number is (165 - 140 ) = 25 The answer is (D).