Malcolm borrowed $550 from his parents to buy a used computer. He did not have to
pay them back for the first four months, but starting on the fifth month, he began
paying them back at $50 per month until the loan was paid off.
Trish bought a $650 computer at the same time. She got a loan from the computer
store for the full amount of the loan. At the beginning of every month, starting the
month after she bought the computer, she pays 10% of the remaining balance.
On what month, after the first two, will they owe approximately the same amount?
Round your answer to the whole month if necessary.