Question

Tia takes $50 from her bank account to pay for bus fare for the month. She does this each month for 7 months in a row. Which equation models this situation and represents the change it causes in Tia's bank balance?

Answer 1

Let B0 be her starting balance. Each month she withdraws $50 for 7 months, a total of 50·7 = 350. The equation is

B = B0 − 50·7

or simplified

B = B0 − 350

(Or more generally B = B0 − 50m, with m the number of months; here m = 7.)