A man walks on a straight road from his home to a market ` 2.5 km` away with a speed of `5 km //h`. Finding the market closed, he instantly turns and walks back with a speed of `7.5 km//h`. What is the (a) magnitude of average velocity and (b) average speed of the man, over the interval of time (i) `0` to 30 min `. (ii) 0 to 50 min (iii) 0 to 40 min ?

Options

A. 0, 4
B. 0, 6
C. 0, 8
D. 0, 12

Answer

B

Explanation

(a) `barv_(avg) = (bars_(1)+bars_(2))/(t_(1) + t_(2)),
(b) `v_(avg) = (s_(1) + s_(2))/(t_(1) + t_(2))`