Maria and John's Lemonade Sale

Maria and John are selling lemonade. Maria sells her lemonade for $2 per cup and John sells his for $3 per cup. Together, they sold a total of 50 cups of lemonade and made $120 in total. If we let $m$ represent the number of cups of lemonade Maria sold and $j$ represent the number of cups John sold, we can set up the following system of equations:

1. $$m + j = 50$$

2. $$2m + 3j = 120$$

What is the number of cups of lemonade Maria sold?