question: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
answer:(B)
Stream of consciousness:Speed = 63 * 5/18 = 35/2 m/sec
Time taken = 280 * 2/35 = 16 sec

question:The average of 11 results is 46, if the average of first six results is 49 and that of the last six is 52. Find the sixth result?
Options:
(A) 21
(B) 56
(C) 100
(D) 25
(E) 23
answer:(C)
Stream of consciousness:1 to 11 = 11 * 46 = 506
1 to 6 = 6 * 49 = 294
6 to 11 = 6 * 52 = 312
6th = 294 + 312 506 = 100

question:The speed of a car is 90 km in the first hour and 60 km in the second hour. What is the average speed of the car?
Options:
(A) 22
(B) 75
(C) 44
(D) 28
(E) 12
answer:
(B)
Stream of consciousness:S = (90 + 60)/2 = 75 kmph