If a man swims 4 miles upstream at 1 mph and back downstream to the same point at 4 mph, what is his average speed ?

If a man swims 4 miles upstream at 1 mph and back downstream to the same point at 4 mph, what is his average speed ?

A 0.8 mph

B 1.6 mph

C 2.4 mph

D 3.2 mph

Solution

Correct Answer: Option B

Total 5 ঘণ্টায় যায় 8m

1 ঘণ্টায় যায় 8/5=1.6 m