Answer:
1. 
2. 
Step-by-step explanation:
Given
Variation: inverse Proportion
y = 7, x = 9
Required
- Write an equation connecting y and x
- Find y when x = 21
Given that thee variation is inversely proportional;
This implies that

Convert variation to equation
----------- Equation 1
Where k is the constant of variation
Substitute 7 for y and 9 for x in equation 1

Multiply both sides by 9


Substitute 63 for k in equation 1

Multiply both sides by x


Hence, the equation connecting x and y is 
Solving for when x = 21
Substitute 21 for x in the above equation

Divide both sides by 21


70.17543859649122 percent change , rounded would be 70%, it is a 70% increase, as it goes to 57,000 to 97,000
57 miles because of they are driving 38 miles per hour that means in 1 hour they drive 38 miles. So if they drove for an hour and a half you take 38 and half of 38( which is 15) and you add them together.