The smith family made an $800 down payment and pays $75 per month for new furniture. at the same time the cooper family made a $500 down payment and pays $95 per month for new furniture. after how many months will it be before the amounts they have paid are equal?

Margie is practicing for an upcoming tennis tournament. her first serve is good 20 out of 30 times on average. margie wants to know the estimated probability that her first serve will be good at least four of the next six times she serves. how could she design a simulation for this scenario?