Answer: (D)
Question: A train 210 m long, running with a speed of 63 km/hr will pass a tree in?
Options:
(A) 22 sec
(B) 16 sec
(C) 17 sec
(D) 18 sec
(E) 12 sec
[CoT]: [Speed = 63 * 5/18 = 35/2 m/sec
Time taken = 210 * 2/35 = 18 sec]

Answer: (D)
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) 6 kmph
(C) 5 kmph
(D) 8 kmph
(E) 2 kmph
[CoT]: [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]

Answer: (D)
Question: If the given two numbers are respectively 6% and 18% of a third number, then what percentage is the first of the second ?
Options:
(A) 20%
(B) 25%
(C) 18%
(D) 33 1/3%
(E) none of these
[CoT]: [Here, l = 6 and m = 18
Therefore, first number = l/m x 100% of second number = 6/18 x 100% of second number = 33 1/3% of second number]

Answer: (C)
Question:
The speed of a car is 120 km in the first hour and 60 km in the second hour. What is the average speed of the car?
Options:
(A) 89 kmph
(B) 92 kmph
(C) 90 kmph
(D) 65 kmph
(E) 77 kmph
[CoT]: [S = (120 + 60)/2 = 90 kmph]