Question

The boat is moving alongside the flow of the river, and the distance traveled is 240 km, what is the effective speed of the boat (speed in the direction of the river's flow)?"

a) 40 km/h
b) 40 + a km/h
c) 40 - a km/h
d) a km/h

Answer 1

The effective speed of the boat moving alongside the flow of the river is 40+a km/h, where a is the speed of the river. (option b is the correct answer)

Step-by-step explanation:

When a boat moves alongside the flow of a river, its effective speed is the sum of its speed in still water and the speed of the river. Let's denote the speed of the boat in still water as 40 km/h and the speed of the river as km/h. The effective speed is given by 40+a km/h. This is because the river's flow adds to the boat's speed, making it move faster. The total distance traveled is 240 km, and the effective speed is the ratio of the total distance to the time taken. Therefore, the effective speed is 240 km divided by the time taken in hours, giving 40+a km/h.

The effective speed of the boat moving alongside the flow of the river is represented by the expression 40+a km/h, where a is the speed of the river. Option (b) 40+a km/h is the correct answer.