5) Joy and Cullen put some money into their money boxes every week. The amount of money (y), in dollars, in their money boxes after a certain amount of time (x), in weeks, is shown by the equations below: Joy: y = 30x + 20 Cullen: y = 20x + 90
a) After how many weeks will Joy and Cullen have the same amount of money in their money boxes?
b) What is that amount?