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?

a. once per month
b. every three weeks
c. every two months

Given:
Principal: 3,750

savings account at local bank. 1.75% p.a.
3,750 * 1.75% * 1 yr = 65.63 interest per 
3,750 + 65.63 = 3,815.63 ending balance for the year.

online savings account. 3.25% interest, will be charged $4 every times you make an ATM withdrawal.

3,750 * 3.25% * 1 yr = 121.88 annual interest 
3,750 + 121.88 = 3,871.88 ending balance for the year. no wdl.

a. 1 wdl per month = 4 x 12months = 48
3,871.88 - 48 = 3,823.88 ending balance

b. every 3 weeks wdl. 52 wks / 3 wks = 17.33 or 17 times.
4 x 17 = 68 
3,871.88 - 68 = 3,803.88 ending balance

c. every 2 months . 12 months/2 = 6 times
4 x 6 = 24
3,871.88 - 24 =  3,847.88 ending balance.

You must make a withdrawal every three weeks to make the local savings account a better deal than the online savings account.