q: A can do a piece of work in 20 days. B in 15 days A and C in 12 days. In how many days can A finish the work if he is assisted by B on one day and C on the next, alternately?
Options:
(A) 7 days
(B) 8 days
(C) 3 days
(D) 9 days
(E) 2 days
a: Stream of consciousness: A + B = 1/20 + 1/15 = 7/60
A + C = 1/20 + 1/12 = 8/60
7/60 + 8/60 = 15/60 = 1/4
4 days * 2 = 8 days The answer is (B).

question: Three people took GMAT practice tests in which the minimum and maximum possible scores are 200 and 800, respectively. They each took a test 4 times, and no one scored below 610 or over 780. If the individual ranges of the three people's scores in those 4 practice tests were 50, 80 and 90, what is the difference between the maximum and minimum possible ranges of all their scores put together.
Options:
(A) 70
(B) 80
(C) 90
(D) 100
(E) 110
answer: Stream of consciousness: According to the information in the question the maximum range would be between 610 and 780(170). The minimum range would be the greatest range for any one individual, which is listed in the problem as 90. So the difference between these would be 170-90 or 80. The answer is (B).

q: The no. of girls in a class are 7times the no. of boys, which value cannever be the of total students?
Options:
(A) 20
(B) 35
(C) 30
(D) 40
(E) 42
a: Stream of consciousness: Let the boys are X, then girls are 7X, total = X+7X = 8X
So it should be multiple of 8, 30 is not a multiple of 8. The answer is (C).

question: A boy runs 200 metres in 24 seconds. What is his speed?
Options:
(A) 20 km/hr
(B) 24 km/hr
(C) 30 km/hr
(D) 32 km/hr
(E) 34 km/hr
answer: Stream of consciousness: 200/24 * 18/5 = 30 km/hr The answer is (C).

q: The speed of a boat in still water is 60kmph and the speed of the current is 30kmph. Find the speed downstream and upstream?
Options:
(A) kmph
(B) kmph
(C) kmph
(D) kmph
(E) kmph
a: Stream of consciousness: Speed downstream = 60 + 30 = 90 kmph
Speed upstream = 60 - 30 = 30 kmph The answer is (D).

q: Find the area of the quadrilateral of one of its diagonals is 20 cm and its off sets 9 cm and 6 cm?
Options:
(A) 328
(B) 150
(C) 279
(D) 277
(E) 267
a:
Stream of consciousness: 1/2 * 20(9 + 6) = 150 cm2 The answer is (B).