Question

2. A boat can travel with a speed of 22 kmph in still water. If the speed of the
stream is 5 kmph, find the time taken by the boat to go 54 km downstream?
(B) 2 hrs.
(A) 3 hrs.
(D) 5 hrs.
(C) 4 hrs.​

Answer 1

Answer:

The correct answer is option B: 2 hrs

Step-by-step explanation:

The direction along the stream is called downstream.

And, the direction against the stream is called upstream.

Suppose the speed of a boat in still water is x km/hr and the speed of the stream is y km/hr, then:

Speed downstream = (x + y) km/hr.

Now, from the given data:

Speed of boat in still water=x= 22kmph

Speed of the stream= y = 5 kmph

Hence, Total speed of the boat= (x+y) = 22+ 5 =27kmph

Let the time taken by the boat be x:

Now,

$speed = \frac{distance}{time}$

$27= \frac{54}{x}$

$x = \frac{54}{27}$

$x = 2hrs$

Therefore, Time taken by the boat is 2hrs.