# Boats and Streams Practice Quiz

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# Boats and Streams Practice Quiz

### Introduction

The article Boats and Streams Practice Quiz provides information about Boats and Streams, a important topic of Quantitative Aptitude section. Consists of different types Boats and Streams questions with solutions useful for candidates preparing for different competitive examinations like RRB ALP/Technical Exams/Junior Engineer Recruitment Exams, SSC, IBPS PO Exams and etc.

### Quiz

1. A boat goes 20 km upstream in 2 hours and downstream in 1 hour. How much time this boat will take to travel 30 km in all still water?

A. 1 hr
B. 2 hrs
C. 1.5 hrs
D. 2.5 hrs

Explanation –

Let $${v}_{1}$$ be the speed of boat in still water and $${v}_{2}$$ be the speed of current

$${v}_{1} + {v}_{2}$$ = $$\frac {20}{1}$$ = 20 ……(1)

$${v}_{1} – {v}_{2}$$ = $$\frac {20}{2}$$ = 10 ……(2)

From equations (i) and (ii) we get

$${v}_{1}$$ = 15 km/hr

$$\frac {d}{{v}_{1}}$$ = $$\frac {30}{15}$$ = 2 hrs

2. In the above question, the speed at which the stream is flowing is

A. 10 km/hr
B. 20 km/hr
C. 15 km/hr
D. 5 km/hr

Explanation –

From the above two equation, we get $$\frac {d}{{v}_{2}}$$ = 5 km/hr

3. A boat travels 10 km in 1 hr downstream and 14 km in 2 hrs upstream. How much time this boat will take to travel 17 km in still water?

A. 1 hr
B. 2 $$\frac {1} {2}$$hrs
C. 2 hrs
D. 2 $$\frac {1} {2}$$hrs

Explanation –

$${v}_{1} + {v}_{2}$$ = $$\frac {10}{1}$$ = 10 ……(1)

$${v}_{1} – {v}_{2}$$ = $$\frac {14}{2}$$ = 7 ……(2)

Adding equations (i) and (ii), we get

$${v}_{1}$$ = $$\frac {17}{2}$$ km/hr

$$\frac {d}{{v}_{1}}$$ = $$\frac {17}{\frac{17}{2}}$$ = 2 hrs

4. A man goes by motor boat a certain distance up stream at 15 km/hr and return the same
downstream at 20 km/hr. The total time taken for the journey was 7 hrs. Find how far did he go.

A. 60 km
B. 50 km
C. 40 km
D. 120 km

Explanation –

$$\frac {d}{20} + \frac {d}{10}$$ = 7

d = 60 km

5. A man can row upstream a distance of $$\frac {2} {3}$$ km in 10 minutes and returns the same distance downstream in 5 minutes. Ratio of manâ€™s speed in still water and that of the stream will be

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

Explanation –

$${v}_{1} – {v}_{2}$$ = $$\frac {\frac{2}{3}km}{10 min}$$

i.e, $${v}_{1} – {v}_{2}$$ = $$\frac {2}{30}$$ km/min ……(1)

and $${v}_{1} + {v}_{2}$$ = $$\frac {\frac{2}{3} km}{5 min}$$ = 10

$${v}_{1} + {v}_{2}$$ = $$\frac {2}{15}$$ = 7 ……(2)

Solving equation (i) and (ii), we get

$${v}_{1}$$ = $$\frac {2 + 4}{60}$$ km/min = $$\frac {6}{60}$$ km/min = $$\frac {1}{10}$$ km/min

$${v}_{2}$$ = $$\frac {4 – 2}{60}$$ km/min = $$\frac {2}{60}$$ km/min = $$\frac {1}{30}$$ km/min

$$\frac{{v}_{1}}{{V}_{2}}$$ = $$\frac {1}{10}$$ * $$\frac {30}{1}$$ = 3 : 1

1. A man can row a certain distance down stream in 6 hours and return the same distance in 9 hours. If stream flows at the rate of 2 km/hr, then what will be manâ€™s speed if he rows in still water?

A. 10 km/hr
B. 12 km/hr
C. 14 km/hr
D. 15 km/hr

Explanation –

$$( {v}_{1} + {v}_{2}) {t}_{1}$$ = $$( {v}_{1} – {v}_{2}) {t}_{2}$$

i.e, $$( {v}_{1} + {v}_{2}) * 6$$ = $$( {v}_{1} – {v}_{2}) * 9$$

$$( {v}_{1}$$ = 10 km/hr

2. A boat against the current of water goes 9 km/hr and in the direction of the current 12 km/hr. The boat takes 4 hours and 12 minute es to move upward and downward direction from A to B. What is the distance between A and B?

A. 21.6 km
B. 21.0 km
C. 22 km
D. 30 km

Explanation –

$$\frac {d}{9} + \frac {d}{12}$$ = $$4 \frac {12}{60}$$

d = 21.6 km

3. A man takes 3 hours and 45 minutes to boat 15 km with the current in a river and 2 hours 30 minutes to cover a distance of 5 km against the current. Speed of the boat in still water and speed of the current respectively will be

A. 3 km/hr, 1 km/hr
B. 1 km/hr, 3 km/hr
C. 2 km/hr, 5 km/hr
D. none of these

Explanation –

$$({v}_{1} + {v}_{2})$$ = $$\frac {15}{3 \frac {3}{4}}$$ = 4 km/hr

$$({v}_{1} – {v}_{2})$$ = $$\frac {5}{2 \frac {1}{2}}$$ = 2 km/hr

Solving equations (i) and (ii), we get

$${v}_{1}$$ = 3 km/hr and $${v}_{2}$$ = 1 km/hr

4. A boat can be rowed 6 km/hr along the current and 4 km/hr against the current. Speed of the current and speed of the boat in still water, respectively will be

A. 1 km/hr, 5 km/hr
B. 5 km/hr, 1 km/hr
C. 2 km/hr, 4 km/hr
D. none of these

Explanation –

$$({v}_{1} + {v}_{2})$$ = 6 …..(1)

$$( {v}_{1} – {v}_{2})$$ = 4 …..(2)

From equations (i) and (ii), we get

$${v}_{1}$$ = 5 km/hr and $${v}_{2}$$ = 1 km/hr

5. A boat moves down the stream at the rate of 1 km in 6 minutes and up the stream at the rate of
1 km in 10 minutes. The speed of the current is

A. 2 km/hr
B. 1 km/hr
C. 1.5 km/hr
D. 2.5 km/hr

Explanation –

$$({v}_{1} + {v}_{2})$$ = $$\frac {1 km}{6 min}$$ = 10 km/hr …(1)

$$({v}_{1} – {v}_{2})$$ = $$\frac {1 km}{10 min}$$ = 6 km/hr ….(2)

subtracting equation (2) from (1), we get

$${v}_{1}$$ = 2 km/hr

1. A man can row 5 km per hour in still water. If the river is flowing at 1km per hour, it takes him 75 minutes to row to a place and back. How far is the place?

A. 3 km
B. 2.5 km
C. 4 km
D. None of these

Explanation –

$$\frac {d}{5 + 1} + \frac {d}{5 – 1}$$ = $$\frac {75}{60}$$

$$\frac {2d + 3d}{12}$$ = $$\frac {5}{4}$$

d = 3 km

2. Speed of a boat in still water is 7 km/hr and speed of the stream is 1.5 km/hr . How much time will it take to move up is stream of a distance 7.7 km?

A. 75 minutes
B. 84 minutes
C. 72 minutes
D. None of these

Explanation –

t = $$\frac {d}{{v}_{1} + {v}_{2}}$$ = $$\frac {7.7}{7 + 1.5}$$ = $$\frac {7.7}{5.5}$$

= $$\frac {7}{5}$$ hrs = $$\frac {7}{5} * 60 min$$ = 84 min

3. A motorboat takes 2 hours to travel a distance of 9 km down the current and it takes 6 hours to
travel the same distance against the current. What is the speed of the boat in still water in kmph?

A. 3
B. 2
C. 1.5
D. 1

Explanation –

Let the speed of boat in still water and speed of current are x and y km/h respectively.

i.e, Downward speed of boat = (x + y) km/h.

According to question,

x + y = $$\frac {9}{2}$$

2x + 2y = 9 …(i)

x – y = $$\frac {9}{6}$$

2x â€“ 2y = 3 …(ii)

On solving equations (i) and (ii), we get

x = 3, y = $$\frac {3}{2}$$