Answer: Jon purchased 4 staplers and 7 three hole punchers.
Explanation:
Let x be the number of staplers and y be the number of three hole punches purchased by Jon.
Then the equation for total items will be
............(1)
And the equation for the total cost will be
........................(2)
Multiply eq(1) by 7 and then subtract from eq (2), we get

Put y=7 in eq(1), we get x= 4.
Hence, Jon purchased 4 staplers and 7 three hole punchers.