q: What is the are of an equilateral triangle of side 16 cm?
Options:
(A) 66√3 cm2
(B) 74√3 cm2
(C) 64√3 cm2
(D) 64√5 cm2
(E) 14√3 cm2
a: Stream of consciousness: Area of an equilateral triangle = √3/4 S2
If S = 16, Area of triangle = √3/4 * 16 * 16 = 64√3 cm2; The answer is (D).


question: From a Group of 9 People, Including George and Nina, 4 people are to be selected at random to work on a certain project. What is the probability that 4 people selected will include George but not Nina
Options:
(A) 5/56
(B) 9/56
(C) 15/56
(D) 35/120
(E) 25/56
answer: Stream of consciousness: Number of ways of selecting 4 people out of 9 people = 9C4
In the three members George will always be there in the team. At this step we have vacancy for 3 more members and 8 members are available. Nina cannot be there in the team. So 3 members have to be selected and the number of available members = 8 - Nina = 7
Number of ways to form a 4 member team that includes George and excludes Nina = 7C3
Probability = 7C3/9C4 = 35/120 The answer is (D).


q: A man rows his boat 75 km downstream and 45 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?
Options:
(A) 1 kmph
(B) 6 kmph
(C) 5 kmph
(D) 8 kmph
(E) 7 kmph
a: Stream of consciousness: Speed downstream = d/t = 75/(2 1/2) = 30 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (30 - 18)/2 = 6 kmph The answer is (B).


question: Working alone, Printers X, Y, and Z can do a certain printing job, consisting of a large number of pages, in 12, 30, and 40 hours, respectively. What is the ratio of the time it takes Printer X to do the job, working alone at its rate, to the time it takes Printers Y and Z to do the job, working together at their individual rates?
Options:
(A)  4/11
(B)  1/2
(C)  15/22
(D)  120/7
(E)  11/4
answer: Stream of consciousness: P1 takes 12 hrs
Rate for P2P3 together = 1/30 + 1/40 = 7/120
Therefore they take 120/7
Ratio = 120/7 = The answer is (D).


q: 10 books are placed at random in a shelf. The probability that a pair of books will always be together is ?
Options:
(A) 1/8
(B) 1/2
(C) 1/5
(D) 1/5
(E) 1/3
a: Stream of consciousness: 10 books can be rearranged in 10! ways consider the two books taken as a pair then number of favourable ways of getting these two books together is 9! 2!
Required probability = 1/5 The answer is (C).


q: A pharmaceutical company received $5 million in royalties on the first $40 million in sales of and then $9 million in royalties on the next $210million in sales. By approximately what percentage did the ratio of royalties to sales decrease from the first $40 million in sales to the next $210 million in sales?
Options:
(A) 8%
(B) 15%
(C) 45%
(D) 52%
(E) 66%
a:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Stream of consciousness: (9/210)/(5/40) = 12/35 = 34% it means that 9/210 represents only 34%. Therefore a decrease of 66%. The answer is (E).