Question: At Al 's Rent-a-Center , it costs 30 dollars more per month to rent a leather couch than it does to rent a microfiber couch. Pauline rented a leather couch for 8 months and then exchanged it for a microfiber couch , which she rented for 12 months. She paid a total of 1620 dollars to rent these couches. Solve this system of equations to find the monthly rental charge for the leather couch , in dollars.
Answer: 99