Aren has an empty coin jar. She adds two dimes, three quarters, and six nickels into a money jar. The next day, she removes two quarters and four nickels.

Harry owes the bank money. to repay his debt, he paid $150 back to the bank each month. after 10 months, his remaining debt was $6900. what was the original amount of harry's debt? how long did it take harry to pay back his entire debt?