31. Mr. kavin walks at 4/5 of his normal speed and takes 60 minutes more than the usual time. What will be the new time taken by Mr.kavin?

A. 260 minutes B. 235 minutes C. 220 minutes D. 300 minutes

Answer Answer: Option D Explanation: 4/5 of speed = 5/4 of original time
5/4 of original time = original time + 60 minutes
1/4 of original time = 60 minutes
Thus, original time = 60*4 = 240 minutes = 240+60 = 300 minutes

32. A man takes twice as long to row a distance against the stream as to row the same distance in favor of the stream.The ratio of the speed of the boat ( in still water) and the stream is

A. 2:1 B. 3:1 C. 3:2 D. 4:3

Answer Answer: Option B Explanation: Let man's rate upstream be X km/ph.Then his rate downstream = 2x km/ph
Speed in still water : Speed of stream = (2x + x /2): 2x-x/2) = 3x/2:x/2 = 3:1

33. A boat running upstream takes 8 hours 48 minutes to cover a certain distance while it takes 4 hours to cover the same distance running downstream.What is the ratio between the speed of the boat and speed of the water current respectively?

A. 2:1 B. 3:2 C. 8:3 D. Cannot be determined

Answer Answer: Option C Explanation: Let the man's rate upstream be x km/ph and that downstream be y km/ph.Then distance covered upstream in 8 hrs 48 mins= Distance covered downstream in 4 hours => (x*8 4/5) = (y*4) => 44/5x = 4y => y=11/5 x
Required ratio = (y+x/2): (y-x/2) = (16x/5*1/2): (6x/5*1/2) = 8/5:3/5 = 8:3

35. A man can row 9 1/3 km/hr in still water and finds that it takes him thrice as much time to row up than as to row down the same distance in the river. the speed of the current is/

A. 3 1/3 km/hr B. 3 1/9 km/hr C. 4 2/3 km/hr D. 4 1/2 km/hr

Answer Answer: Option C Explanation: Let speed upstream be x km/hr.then, speed downstream = 3x km/hr.
speed in still water = 1/2 (3x+x) km/hr = 2x km/hr.
Therefore 2x =28/3 => x= 14/3.
so, speed upstream = 14/3 km/hr ; speed downstream =14 km/hr
Hence, speed of the current = 1/2 (14- 14/3) km/hr = 14/3 km/hr =4 2/3 km/hr.