We know that,
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 =
= 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 =
= 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.
<u>Answer:</u>

<u>Solution:</u>
Given: x=30
To solve: 
On substituting the value of x,

On dividing 30 and 5 we get,

So, the option is 15.
The explanatory variable is the amount of exposure the student is given to classical music.
The first option and the third one
Answer:

Step-by-step explanation:

Hope this helps!