An office supply store sells pens for $3 and notebooks for $5. Before school started, the store sold 12 more pens than notebooks and made $324. Which system of equations could be used to find the number of pens, p, and notebook, n that the store sold that day?

P = N + 12

5N + 3P = 324

Substitute N+12 for P in second equation and solve for N. Insert that value into the first equation and solve for P. Check by inserting both values into the second equation.

To find the system of equations that could be used to solve this problem, let's start by setting up the two equations based on the given information:

1) The store sold 12 more pens than notebooks:
p = n + 12

2) The total revenue made by selling pens and notebooks is $324:
3p + 5n = 324

So, the system of equations is:
p = n + 12
3p + 5n = 324

Now, you can use these equations to solve for the values of p (the number of pens) and n (the number of notebooks) that the store sold that day.