Final answer:
Kathy saved $2,160 by paying off the loan early.
Step-by-step explanation:
To calculate the amount saved by paying off the loan early, we need to find the total interest paid for 10 years and subtract the total interest paid for 7 years.
For a loan of $12,000 with an annual interest rate of 6%, the total interest paid for 10 years would be $12,000 * 0.06 * 10 = $7,200.
The total interest paid for 7 years would be $12,000 * 0.06 * 7 = $5,040.
Therefore, Kathy saved $7,200 - $5,040 = $2,160 by paying off the loan early.