Question

Two boats left an island at the same time to return to the same home port. Their rates of speed differ by 4km/h. The faster boat reached the port in 3 hours. The other boat took 30 minutes longer. Find the average speed of each boat.

Answer 1

Average speed of the two boats are 28 km/hr. and 24 km/hr.

Explanation:

Let the average speed of the boat with larger speed is x km/h and that of the other boat is y km/h.

Now, given that x - y = 4 ...... (1)

If the distance, that the first boat covers in 3 hrs. is d km then the second boat covers d km in 3.5 hrs.

Therefore,
`x =(d)/(3)` and
`y = (d)/(3.5)`

Now, from equation (1), we can get
`(d)/(3) -(d)/(3.5) =4`

⇒
`d((0.5)/(3 * 3.5) ) =4`

⇒
`x= (d)/(3) = (4 * 3.5)/(0.5) =28` km/hr.

Again,
`y= (d)/(3.5) =(4 * 3)/(0.5)= 24` km/hr.

Therefore, the average speed of the two boats is 28 km/hr. and 24 km/hr. (Answer)