Question

Lena and Ras drive to work. Lena drives 24 miles in 1.5 hours. Ras drives 36 km in 1 hour 15 min. Work out the difference between their average speeds in km/h. 1 mile = 1.6 km

Answer 1

Answer:

Difference = 3.2 km/h

Step-by-step explanation:

Given that,

Lena drives 24 miles in 1.5 hours. Ras drives 36 km in 1 hour 15 min.

For average speed of Lena,

d = 24 miles = 38.4 km

t = 1.5 h

$v=\dfrac{38.4}{1.5}= 25.6\ km/h$

For average speed of Ras,

d = 36 km

t = 1h 15 min = 1.25 h    

$v=\dfrac{36}{1.25}=28.8\ km/h$

Difference = 28.8-25.6

= 3.2 km/h

So, the difference between their average speed is 3.2 km/hr.