Nafi can row down a 20- mile stream in 2 hours and can return in upstream in 5 hours.What is his average rate,in miles per hour,for the entire trip?
a.10/7
b.7/2
c.20/6
d.3
e.40/7
1 answer
avg rate = (total distance)/(total time) = (20+20)/(2+5) = ?