Mary Contrary is offered a $1,600 loan for a year to be paid back in equal quarterly principal installments of $400 each. If Mary is offered the loan at 6 percent simple interest, how much in total interest charges will she pay? Would Mary be better off (in terms of lower interest cost) if she were offered the $1,600 at 5 percent simple interest with only one principal payment when the loan reaches maturity? What advantage would this second set of loan terms have over the first set of loan terms?