Answer:
5 months
Explanation:
Let:
[] b be the number of cards Bob has
[] p be the number of cards Peter has
[] m be every month that passes, "per month," etc
"Bob has 100 collectible baseball cards and is sending 15 per month to his grandson Tom"
b = 100 - 15m
"He [Peter] plans to purchase 5 cards per month."
p = 5m
It asks us to graph the system. The point of intersection is the solution to our problem.
-> See attached