Correct Answers: | |

Wrong Answers: | |

Unattempted: |

### Question 1

A boat can travel 392 km downstream in 28 hours. If it covers the same distance upstream in 98 hours, what is the rate of flow of the stream?

**A**

5 kmph.

**B**

6 kmph.

**C**

4 kmph.

**D**

8 kmph.

**Soln.**

**Ans: a**

The downstream speed = $392/28$ = 14 km/h, and the upstream speed = $392/98$ = 4 km/h. By the shortcut method, the speed of the stream is half of the difference between the downstream and upstream speeds of the boat. So the required speed = ${14 - 4}/2$ = 5 km/h.

### Question 2

A boat has a downstream speed of 8 km/h and an upstream speed of 6 km/h. What is the speed of the boat in still water?

### Question 3

The speed of a boat in still water is 12 km/h and rate of flow of the stream is 4 km/h. If it travels upstream for 6 hours, what is the distance travelled by the boat during the journey?

### Question 4

The speed of an aircraft in still air is 14 km/h and rate of wind is 4 km/h. If it travels along the direction of the wind for 3 hours, what is the distance travelled by the aircraft during the journey?

### Question 5

The product of the downstream and upstream speeds of a boat in a river is 8. What is the difference between the squares of the speed of the boat in still water and the speed of the stream?

**A**

8.

**B**

10.

**C**

12.

**D**

16.

**Soln.**

**Ans: a**

Let the speed of the boat in still water be u, and let v be the speed of the stream. The product of the upstream and downstream speeds of the boat is $(u + v) × (u - v)$, which is $u^2 - v^2$, and, therefore, the required answer = 8.

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This Blog Post/Article "Boats and Streams Quiz Set 010" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Updated on 2019-08-18.