Linear models word problems

Solve general word problems about real-world relationships that can be modeled by linear equations or functions.

Problem

Harry owes the bank money. To repay his debt, he paid dollar sign, 150 back to the bank each month. After 10 months, his remaining debt was dollar sign, 6900.
What was the original amount of Harry's debt?
spacedollar sign
How long did it take Harry to pay back his entire debt?
space
months