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.