question:Find the invalid no.from the following series 13, 18, 25, 30, 37, 40
Options:
(A) 13
(B) 18
(C) 40
(D) 30
(E) 37
answer:(C)
Stream of consciousness:The differences between two successive terms from the beginning are 7, 5, 7, 5, 7, 5. So, 40 is wrong.

question:A man rows his boat 85 km downstream and 45 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?
Options:
(A) 7 kmph
(B) 5 kmph
(C) 3 kmph
(D) 8 kmph
(E) 2 kmph
answer:(D)
Stream of consciousness:Speed downstream = d/t = 85/(2 1/2) = 34 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (34 - 18)/2 = 8 kmph

question:What amount does Kiran get if he invests Rs. 18000 at 12% p.a. simple interest for four years?
Options:
(A) 29893
(B) 26640
(C) 29989
(D) 28800
(E) 29883
answer:
(B)
Stream of consciousness:Simple interest = (18000 * 4 * 12)/100 = Rs. 8640
Amount = P + I = 18000 + 8640 = Rs. 26640