Question 1033018
4 mph=1/15 mile per minute
5(d+1/15)=13(d-1/15)
5d+5/15=13d-13/15
Multiply through by 15, we get:
75d+5=195d-13
120d=18
d=18/120=.15 miles per minute, or 9 miles per hour in still water!!!!!!!