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 450 or over 650. If the individual ranges of the three people's scores in those 4 practice tests were 30, 80 and 110, what is the difference between the maximum and minimum possible ranges of all their scores put together.
Options:
(A) 90
(B) 120
(C) 50
(D) 70
(E) 100
answer: Stream of consciousness: According to the information in the question the maximum range would be between 450 and 650(200). The minimum range would be the greatest range for any one individual, which is listed in the problem as 110. So the difference between these would be 200-110 or 90. The answer is (A).

q: Find the value of y from (12)^3 x 6^4 432 = y?
Options:
(A) 3452
(B) 2343
(C) 2435
(D) 2578
(E) 5184
a: Stream of consciousness: Given Exp. = (12)3 x 64 = (12)3 x 64 = (12)2 x 62 = (72)2 = 5184
432 12 x 62 The answer is (E).

question: Every year an amount increases by 1/6th of itself. How much will it be after two years if its present value is Rs.64000?
Options:
(A) 87111
(B) 81007
(C) 81008
(D) 81066
(E) 81022
answer: Stream of consciousness: 64000* 7/6 * 7/6 = 87111 The answer is (A).

q: A, B, C, and D are four points, any three of which are non-collinear. Then, the number of ways to construct three lines each joining a pair of points so that the lines do not form a triangle is
Options:
(A) 7
(B) 8
(C) 9
(D) 24
(E) 23
a: Stream of consciousness: To construct 2 lines, three points can be selected out of 4 in 4 x 3 x 2 = 24 ways. Now, if third line goes from the third-point to the first point, a triangle is formed, and if it goes to the fourth point, a triangle is not formed. So, there are 24 ways to form a triangle and 24 ways of avoiding triangle. The answer is (D).

question: The speed of a boat in still water is 70kmph and the speed of the current is 20kmph. Find the speed downstream and upstream?
Options:
(A) kmph
(B) kmph
(C) kmph
(D) kmph
(E) kmph
answer: Stream of consciousness: Speed downstream = 70 + 20 = 90 kmph
Speed upstream = 70 - 20 = 50 kmph The answer is (D).

question: What is the greatest positive integer x such that 5^x is a factor of 125^10?
Options:
(A) 5
(B) 9
(C) 10
(D) 20
(E) 30
answer:
Stream of consciousness: 125^10 = (5^3)^10 = 5^30 The answer is (E).