So there are 15 food booths and 20 game booths. Food booths cost 100 dollars. Game booths cost 50.
100 * 15 = 1500
50 * 20 = 1000
And 5 dollars extra for a day, and 7 dollars extra for a day. Multiply by how many days (d).
7 * d = 7d.
5 * d = 5d.
This means that the expression is:
1500 + 5d + 50 + 7d.
1550 + 12d.