A commuter has $245 in his commuter saving account this account changes by -15 each week he buys a ticket
amount in account = 245 - 15 n
where n is number of weeks
after 16 weeks I suppose he stays home :)
To find out how many weeks the commuter can buy tickets before running out of money, we need to divide the total amount in the commuter savings account ($245) by the amount it changes each week (-$15).
245 รท (-15) = -16.33
Since we can't have a fraction of a week, we'll round down to the nearest whole number. So the commuter can buy tickets for approximately 16 weeks before running out of money.