Question

161 a motorboat is able to travel at a speed of 20 km/hr in still water. in 8 hours, the boat traveled 20 km against the current and 180 km with the current. find the speed of the current of the river.

Answer 1

The speed of the current of the river is 2.5 km/hr.

Step-by-step explanation:

To find the speed of the current, we can use the concept of relative velocity. Let's assume the speed of the current is 'c' km/hr. Against the current, the effective speed of the boat would be 20 - c km/hr, and with the current, the effective speed of the boat would be 20 + c km/hr.

Using the formula: speed = distance/time, we can set up two equations:

20 - c = 20/8 (since the boat traveled 20 km against the current in 8 hours)

20 + c = 180/8 (since the boat traveled 180 km with the current in 8 hours)

Simplifying these equations, we get:

c = 2.5 km/hr

So, the speed of the current is 2.5 km/hr.