Average speed for a 19 km and 61 km journey at different speeds

[chawki]

Homework Statement

A car is driven 19 km at an average speed of 91 km/h and after that 61 km at an
average speed of 65 km/h.

Homework Equations

What was the average speed of the whoIe joumey?

The Attempt at a Solution

t1=19/91 = 0.208 h
t2=61/65 = 0.938 h

average speed = (19+61)/(0.208+0.938)
average speed = 69.808 km/h

 

[SammyS]

This looks fine.

 

[tiny-tim]

looks ok!

 

[ashishsinghal]

its correct!