Question

A theater charges $9 for an adult ticket and $4 for a child ticket.

All 1020 tickets were sold and $7680 of revenue was brought in.
How many adult tickets were sold?

Answer 1

720 adult tickets! Hope it helped

Answer 2

a = adult
c = children

a + c = 1020 so a= 1020 - c
9a + 4c = 7680

substitute a= 1020 - c into 9a + 4c = 7680

9a + 4c = 7680
9(1020 - c) + 4c = 7680
9180 - 9c + 4c = 7680
-5c = -1500
c = 300

a= 1020 - c
a = 1020 - 300
a = 720

answer: 720 adult tickets were sold