Nelly wants to buy pizza for herself and her 14 friends. Each pizza costs $12 and can feed 3 people. If Nelly earns $4 a night babysitting the neighbors' kids, how many nights will she have to babysit to afford the pizza?
She needs to buy 15 / 3 = <<15/3=5>>5 pizzas.
The pizzas cost 5 * $12 = $<<5*12=60>>60 total.
It will take her $60 / $4 = <<60/4=15>>15 nights worth of babysitting to afford the pizza.
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