(Ans). (E)
(Question). A man rows his boat 78 km downstream and 56 km upstream, taking 4 hours each time. Find the speed of the stream?
Options:
(A) 6
(B) 5
(C) 7
(D) 8
(E) 3
(CoT). Speed downstream = d/t = 78/(4) = 20 kmph
Speed upstream = d/t = 56/(4) = 14 kmph
The speed of the stream = (20 - 14)/2 = 3 kmph


(Ans). (A)
(Question). There are four prime numbers written in ascending order of magnitude. The product of the first three is 385 and of the last three is 1001. Find the fourth number?
Options:
(A) 5
(B) 7
(C) 11
(D) 13
(E) 15
(CoT). (385/1001) = 5/13 First Number is 5


(Ans). (E)
(Question). If the ratio of boys to girls in a class is B and the ratio of girls to boys is G; then 10 (B + G) is ?
Options:
(A) Equal to 3
(B) Less than 3
(C) More than 3
(D) Less than 1/3
(E) none of these
(CoT). Let number of boys = x
Let number of girls = y
Therefore x/y = B and y/x = G
10(B + G) = 10[(x/y) + (y/x)] = 10[(x2 + y2)/xy] > 10


(Ans). (B)
(Question).

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
A train 280 m long, running with a speed of 63 km/hr will pass a tree in?
Options:
(A) 18 sec
(B) 16 sec
(C) 76 sec
(D) 15 sec
(E) 17 sec
(CoT). Speed = 63 * 5/18 = 35/2 m/sec
Time taken = 280 * 2/35 = 16 sec