The speed of the current in the river is 4 mph about travel 17 miles downstream with the current in the this river in the same time that it travels 9 miles upstream against the current find the speed of the boat in the Stillwater

Step-by-step explanation:

b = speed of boat in still water

traveling downstream, the boat goes (b+4 miles)/hour.

traveling upstream the boat goes (b-4 miles)/hour.

Time to travel 17 miles downstream = 17 miles × (1 hour)/(b+4 miles)

Time to travel 9 miles upstream = 9 miles × (1 hour)/(b-4 miles)

17 miles × (1 hour)/(b+4 miles) = 9 miles × (1 hour)/(b-4 miles)

17/(b+4) = 9/(b-4)

cross-multiply denominators:

17(b-4) = 9(b+4)

17b - 68 = 9b + 36

8b = 104

b = 13 miles per hour

b

step-by-step explanation: