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?

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).