Respuesta :

musiclover10045
Distance = Rate x Time

Let x = rate of the current

6 times the speed of the current = 6x

The rate upriver ( going against the current) would be 6x -x = 5x

The rate downriver ( going with the current ) = 6x+x = 7x

Time to travel up river = 150 miles / 5x

Time to travel down river = 350 / 7x
 
It took 3 hours more to go down river

We now have 150/5X +3 = 350/7x

Simplify 150/5x by dividing 150 by 5 to get 30/x

Simplify 350/7x by dividing 350 by 7 to get 50/x

We now have 30/x +3 = 50/x

Remove fractions by multiplying every term by x

30 + 3x = 50

Subtract 30 from each side:

3x = 20

Divide both sides by 3 to get x
x = 20/3
x = 6.67 ( speed of the current)

The rate of the boat in still water from above is 6x

6x = 6 *6.67 = 40 miles per hour






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