At the beginning of the month, Ken has $600 in his savings account. He checks at the end of
the month, and there are four transactions listed on the account: +$230, -$150, +$800, -$720.
He then takes the money from his savings account to pay a bill of $90. What percentage
his original amount does he have at the end of the month after paying his bill? (Round your
final answer to the nearest hundredth of a percent.)