Question

Greta is taking a road trip from Cincinnati to San Francisco. On the first day, she drove 650 miles in 10 hours. On the second day, she got a later start and drove 540 miles in 8 hours. How many miles per hour faster was her average speed the second day? Write your answer as a decimal or a whole number.

Answer 1

Given:

On the first day, she drove 650 miles in 10 hours.

On the second day, she got a later start and drove 540 miles in 8 hours.

To find:

Difference between average speed of second day and first day.

Solution:

We know that,

$Speed=\dfrac{Distance}{Time}$

On the first day, she drove 650 miles in 10 hours.  So, the average speed is

$Speed=\dfrac{650}{10}$

$Speed=65$

So, the average speed on first day is 65 miles per hour.

On the second day, she got a later start and drove 540 miles in 8 hours.

$Speed=\dfrac{540}{8}$

$Speed=67.5$

So, the average speed on second day is 67.5 miles per hour.

Difference between average speed is

$67.5-65=2.5$

Therefore, the average speed on the second day is 2.5 miles per hour is faster than first day.