Question

Julia can finish a 20-mile bike ride in 1.2 hours. Katie can finish the same bike ride in 1.6 hours. How much faster does Julia ride than Katie? Distance Rate Time Julia 20 1.2 Katie 20 1.6 4.2 mph 12.5 mph 15.4 mph 16.7 mph

Answer 1

Well, if Julia finishes a 20-mile ride in 1.2 hours, her speed is 20/1.2, or 16.667 miles per hour. Katie's speed is 20/1.6, or 12.5 miles per hour. So Julia is 16.667-12.5 miles per hour faster than Katie, or 4.167.

Answer 2

We know that,$speed = \frac{distance}{time}$

Julia can finish a 20-mile bike ride in 1.2 hours.

The distance Julia travels is 20 miles and the time she takes is 1.2 hours.

So, Julia's speed = $\frac{20}{1.2}$ = 16.67 mph

Katie can finish the same bike ride in 1.6 hours.

The distance Katie travels is 20 miles and the time she takes is 1.6 hours.

So, Katie's speed = $\frac{20}{1.6}$ = 12.5 mph

Now, to find how much faster Julia rides than Katie we subtract Katie's speed from Julia's speed.

So, 16.67 mph - 12.5 mph = 4.17 mph = 4.2 mph (approximately)

Thus, Julia rides 4.2 mph faster than Katie.