Simon recently received a credit card with an 18% nominal interest rate. With the card, he purchased a new stereo for $350. The minimum payment on the card is only $10 per month.
a. If Simon makes monthly payments of $30, how many months will it be before he pays off the debt? Round to the nearest month.
b. How much more in total payments will Simon make under the $10 a month plan than under the $30 a month plan? Make sure you use the three decimals places for N.