Tina wants to open a savings account. Bank A requires a $100 deposit to open the account and requires a minimum deposit of $50 a month. Bank B requires a $250 deposit to open the account and requires a minimum deposit of $20 a month. If Tina were to make the minimum monthly deposits in each account, enter the number of months it would take for both accounts to have the same amount of money.

Set up the equation to find it out.
You have to give 100 for Bank A and 250 for Bank B to open an account. You only have to pay it once. However, to keep the account open, you have to pay 50 for Bank A and 20 for Bank B every month. That is why you have the 'm' (month) for the second part.

100 + 50m = 250 + 20m
Subtract 100 from both sides to eliminate it from the equation
50m=150 + 20m
Subtract 20m from both sides to eliminate it from the equation, as well
30m=150
Divide both sides by 30 to eliminate it
m=5

It will take five months to have the same amount of money in both accounts.