You have $3,750 to deposit. If you deposit the money in a savings account at your local bank, you will earn 1.75% annual interest and will be able to make ATM withdrawals at your bank’s ATMs. If you deposit the money in an online savings account, you will earn 3.25% interest, but you will be charged $4 every time you make an ATM withdrawal. Assuming that your ATM withdrawals do not reduce the amount of interest you earn, roughly how often must you make an ATM withdrawal for the local savings account to be a better deal than the online savings account?

Solution-  Annual Interest earned in the local bank = 1.75% of $3750                                                                       = (1.75×$3750)÷100 = $65.625 Annual Interest earned in the online savings account = 3.25% of $3750                                                                      = (3.25×$3750)÷100 = $121.875For the local savings account to be a better deal, let x be the number of withdrawals, then, 4x >(121.875 - 65.625)         4x > 56.25        ∴ x > 14.0625Therefore, for the local bank to be a better deal, he will withdraw roughly about 15 times and more.