If you are preparing for Quantitative Aptitude, Concepts based on Boat and stream are to be studied and understood well. Lets learn and understand concepts of Boat and Stream.

**Formulas For Boat And Stream Questions**

**Downstream / Upstream : ** In Water, the direction along the stream is called Downstream. And the direction against the stream is called Upstream.

If the speed of boat in still water is u km/hr & the speed of stream is v km/hr, then,

**Speed Downstream: (u + v) km/hr**

**Speed Upstream: (u - v) km/hr **

If the Speed Downstream is a km/hr & the Speed Upstream is b km/hr , then:

**Speed in still water = (a + b) / 2 km/hr **

**Rate of stream = (a - b) /2 km/hr **

**Boat And Stream Questions With Answers**

**Q1) A man's speed with the current is 15 km/hr and the speed of the current is 2.5 km/hr. The man's speed against the current is:**

A) 9 km/hr

B) 12.5 km/hr

C) 8.5 km/hr

D) 10 km/hr.

**Solution :**

**Q2) A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:**

A) 5

B) 4

C) 6

D) 10

**Solution :**

**Q3) In one hour, a boat goes 14 km/hr along the stream and 8 km/hr against the stream. The speed of the boat in still water (in km/hr) is:**

A) 8 km/hr

B) 11 km/hr

C) 12 km/hr

D) 10 km/hr

**Solution :**

**Q4) A boatman goes 2 km against the current of the stream in 2 hour and goes 1 km along the current in 20 minutes. How long will it take to go 5 km in stationary water?**

A) 4 hr

B) 2 hr 30 min

C) 2 hr

D) 1 hr 15 min

**Solution :**

**Q5) A boat can travel with a speed of 13 km/hr in still water. If the speed of the stream is 4 km/hr, find the time taken by the boat to go 68 km downstream. **

A) 2 hours

B) 3 hours

C) 4 hours

D) 5 hours

**Solution: **

Time taken to travel 68 km downstream =68/17hrs = 4 hrs.

**Q6) A man can row upstream 10 kmph and downstream 20 kmph. Find the man rate in still water and rate of the stream. **

A) 0,5

B) 5,5

C) 15,5

D) 10,5

**Solution: **

Rate in still water = 1/2(a+b)

Rate of current = 1/2(a-b)

=> Rate in still water = 1/2(20+10) = 15 kmph

=> Rate of current = 1/2(20-10) = 5 kmph

**Q7) A man's speed with the current is 15 km/hr and the speed of the current is 2.5 km/hr. The man's speed against the current is: **

A) 8.5 km/hr

B) 10 km/hr

C) 12.5 km/hr

D) 9 km/hr

**Solution: **

=> speed of the man + speed of the current = 15 km/hr

speed of the current is 2.5 km/hr

Hence, speed of the man = 15 - 2.5 = 12.5 km/hr

man's speed against the current = speed of the man - speed of the current

= 12.5 - 2.5 = 10 km/hr

**Q8) A man takes 20 minutes to row 12 km upstream which is a third more than the time he takes on his way downstream. What is his speed in still water? **

A) 41 km/hr

**B) **36 km/hr

C) 42 km/hr

D) 45 km/hr

**Solution: **

km/hr. Also, time taken for u/s is 1/3 more than for d/s.

distance covered in d / s will be 1/3 more.

Hence distance covered by man for d / s in 20 min. = 12 × (12/3) = 16km.

So speed of d / s = 48 km/hr.

x + y = 48 and x – y = 36 ? x = 42 km/hr.

**Q9) A man's speed with the current is 15 km/hr and the speed of the current is 2.5 km/hr. The man's speed against the current is: **

A) 8.5 km/hr

B) 10 km/hr

C) 12.5 km/hr

D) 9 km/hr

**Solution: **

=> speed of the man + speed of the current = 15 km/hr

speed of the current is 2.5 km/hr.

Hence, speed of the man = 15 - 2.5 = 12.5 km/hr

man's speed against the current = speed of the man - speed of the current = 12.5 - 2.5 = 10 km/hr

**Q10) In one hour, a boat goes 11km along the stream and 5 km against it. Find the speed of the boat in still water **

A) 6

B) 7

C) 8

D) 9