Marcus can drive his boat 36 miles down the river in 3 hours but takes 4 hours to return upstream. Find the rate of the boat in still water and the rate of the current.

With river 12 miles per hour

Against river 9 miles per hour

wv = water velocity  vsw = boat velocity in still water

vsw +wv =  12 mph

vsw -wv = 9 mph

2 * vsw = 21 mph

boat velocity in still water = 10.5

Since vsw + wv = 12 then

water velocity = 1.5 mph

Step-by-step explanation:

180

step-by-step explanation:

12-2=10

20-2=18

18x10=180