Answer: 75%
Explanation:
Over the course of seven years, Carrie went from charging the Millards $8 to charging them $14 per hour.
To calculate the percentage increase, use the following formula:
= (New price - Old Price) / Old price * 100%
= (14 - 8) / 8 * 100%
= 6/8 * 100%
= 75%
Carrie's rate went up by 75%.