Find the smallest number which should be multiplied with 1152 to make it a perfect square.
Options:
(A) 2
(B) 1
(C) 3
(D) 5
(E) 6

1152 = 2*2*2*2*2*2*2*3*3
Required smallest number = 2
2 is the smallest number which should be multiplied with 1152 to make it a perfect square. So the answer is: (A).

The speed of a boat in upstream is 100 kmph and the speed of the boat downstream is 120 kmph. Find the speed of the boat in still water and the speed of the stream?
Options:
(A) 70, 10 kmph
(B) 35, 27 kmph
(C) 110, 10 kmph
(D) 45, 55 kmph
(E) 45, 65 kmph

Speed of the boat in still water = (100+120)/2 = 110 kmph. Speed of the stream = (120-100)/2 = 10 kmph So the answer is: (C).

3 workers transfer a tool weighing 120kg in 12 seconds. How many men are required to transfer it in 9 seconds?
Options:
(A) 4
(B) 5
(C) 6
(D) 7
(E) 8

We have, M1D1H1 = M2D2H2
3*120*12 = M2*120*9
M2 = 3*120*12/120*9 = 4 So the answer is: (A).

A pipe can fill a cistern in 20 minutes whereas the cistern when fill can be emptied by a leak in 30 minutes. When both pipes are opened, find when the cistern will be full?
Options:
(A) 17 minutes
(B) 87 minutes
(C) 60 minutes
(D) 27 minutes
(E) 11 minutes

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
1/20 - 1/30 = 1/60
60 minutes So the answer is: (C).