d A steamer goes downstream - word math

# MCQ Word Problem 1 ( Boat in a stream and distance calculation )

MCQ Word Problem 1: A steamer goes downstream from one port to another in 4 hours, it covers the same distance upstream in 5 hours. If the speed of the stream is 2km/hr,the distance between the two parts is______?

a) 50 km/hr                    b) 60 km/hr                       c) 70 km/hr                        d) 80 km/hr

Solution:

We in this word math  problem know ;

Distance = Speed x Time

So,

$Speed = \frac{Distance}{Time}$

Let Distance between two ports is ‘x’

Upstream

Speed of Streamer = ​$$\frac{x }{5}\frac{Km}{hr}$$

Downstream

Speed of Streamer = ​$$\frac{x }{4}\frac{Km}{hr}$$

We know that ;

Speed of Stream  = ​$$\frac{His Downstream Speed – His Upstream Speed}{2}$$

So,

Speed of Stream =​$$\frac{x/4-x/5}{2}\frac{km}{hr}$$

But given that speed of stream is 2 km/hr;

So,

$2=\frac{x/4-x/5}{2}\frac{km}{hr}$

Simplifying we get;

$x=80$

So for this word math problem,  the distance between two ports is 80 kms – option d is correct! Copyright secured by Digiprove © 2020