Jack and Sue have summer jobs selling newspaper subscriptions door-to-door, but their compensation plans are different. Jack earns a base wage of $15 per hour, as well as $1 for every subscription that he sells. Sue gets $3 per subscription sold, in addition to a base wage of $3 per hour. If they each sell a certain number of subscriptions in an hour, they will end up earning the same amount. How many subscriptions would that be? How much would each one earn?