Question

A dog runs 120 m away from its master in a straight line in 9.0s, and then runs halfway back in
one third the time. Calculate its average speed
(A) 10m/s
(B) 15m/s
(C) 20m/s
(D) 5m/s​

Answer 1

Answer:

d1=120 d2=60m t1=9s t2=3s

As= 120+60/9+3=180/12=45/3=16

Answer 2

Answer:

Hey mate

your answer is option "b"

15m/s

Explanation:

distance 1 = 120m

time 1 = 9s

distance 2 = 60m

time 2 = ⅓ × 9 = 3

average speed = distance/time

speed = 120 + 60

9 + 3

speed = 180/12

speed = 15m/s