Question

The river boat, Delta Duchess, paddled upstream at 12 km/h, stopped for 2 hours of sightseeing, and paddled back at 18 km/h. How far upstream did the boat travel if the total time for the trip, including the stop, was 7 hours?

Answer 1

36 km

Explanation:

Let time taken by upstream=x hours

Upstream speed=12 km/h

Time spend for sightseeing=2 hours

Total time=7 hours

Traveling time=7-2=5 hours

Time taken by downstream=5-x

Downstream speed=18km/h

Distance=
`speed* time`

Using the formula

Distance traveled when Delta Duchess paddled upstream=12 x

Distance traveled when Delta Duchess paddled back=18(5-x)

According to question

`12x=18(5-x)`

`12x=90-18x`

`12x+18x=90`

`30x=90`

`x=(90)/(30)=3 hours`

Substitute the values

Distance traveled when Delta Duchess paddled upstream=
`12* 3=36 km`