1) The time taken by the boat to travel 360 km distance downstream is 60% of the time taken to travel the same distance upstream. If the speed of the stream is 5 kmph, then what is the speed of the boat in still water?

A.10 kmph

B.12 kmph

C.15 kmph

D.20 kmph

E.18 kmph

2) Ravi can row downstream at 18 Km/hr and upstream at 14 Km/hr. Find the speed of Ravi in still water and speed of current.

A.16Km/h and 2Km/h

B.15Km/h and 3Km/h

C.14Km/h and 4Km/h

D.13Km/h and 2Km/h

E.15Km/h and 5Km/h

3) The ratio of the speed of the boat in still water to speed of stream on Thursday is 4:3. If the boat travels 140km along with the current in 4 hours and it will come back in?

A.22 hours

B.25 hours

C.26 hours

D.28 hours

E.None of these

4) A boat row upstream takes 2 hours to cover the distance of 18 km and it takes same time to cover the distance of 54 km in downstream. What is the speed of boat in still water?

A.18 kmph

B.12 kmph

C.20 kmph

D.24 kmph

E.None of these

5) If the time taken by a boat to travels 30 km upstream is twice the time taken by that boat to travel 75 km downstream. If the speed of the stream is 10 kmph, what is the speed of the boat in still water?

A.20 kmph

B.15 kmph

C.25 kmph

D.30 kmph

E.None of these

Answers :

1) Answer: D

Speed of the boat in still water=x

360/(x + 5)=60/100 * (360/(x – 5))

5/(x + 5)=3/(x – 5)

3x + 15=5x – 25

2x=40

x=20 kmph

2) Answer: A

Downstream speed = 18Km/h

Upstream speed = 14 Km/h

Speed in still water = ½ * (18 + 14)

= 16Km/h

Speed of current = 1/2(18-14) = 2Km/h

3) Answer: D

Downstream speed=140/4=35 kmph

Speed of the boat in still water=4x

Speed of the stream=3x

4x + 3x=35

x=5 kmph

Speed of the boat in still water=4x=20 kmph

Speed of the stream=3x=15 kmph

Upstream speed=20 – 15=5 kmph

Time=140/5=28 hours

4) Answer: A

Speed of the upstream = 18/2 = 9 kmph

Speed of the downstream = 54/2 = 27 kmph

Speed of the boat in still water = 1/2 * (downstream speed + upstream speed)

= 1/2 (27 + 9)

= 18 kmph

5) Answer: B

Speed of the boat in still water=x

30/(x – 10) = 2 * [75/(x + 10)]

30(x + 10) = 150 * (x – 10)

30x + 300 = 150x – 1500

120x = 1800

x = 15 kmph