Question

An object covers one 1/3 distance with an average speed of 80 km/h and the next 1/3 distance in average speed of 60km/h if the average speed during the journey was 72 km/h .Find its average speed in the last part.

Answer 1

Answer:

76 km/h

Explanation:

let the avg speed in last part is x then

(80+60+x)/3=72

140+x=216

x=216-140

=76

Answer 2

Answer:

72 = 3/(1/80 + 1/60 + 1/x)

from here x equals to 80km/h

I hope it's correct!