Question

In two or more complete sentences explain how you would set up and solve the following equation: Peter opened his account with $910 and withdrew $40 per week. Marla opened her account with $470 and withdrew $20 weekly. In how many weeks will their accounts be equal?

Answer 1

Peter will have $910 - $40 * x on his account, where x is the number of the weeks. Marla will have $470 - $20 * x.
910 - 40 x = 470 - 20 x
910 - 470 = 40 x - 20 x
440 = 20 x
x = 440 : 20
x = 22
910 - 40 * 22 = 910 - 880 = $30
470 - 20 * 22 = 470 - 440 = $30
Answer: Their accounts will be equal in 22 weeks ( both of them will have $30 ).