Answer:
adult ticket price: $10
child ticket price: $6
Explanation:
let's say an adult ticket costs a dollars and a child ticket costs c dollars
cost of 2 adult tickets = a dollars for each ticket = a + a = 2a
cost of 6 child tickets = 6c
thursday's sales:
2a + 6c = 56
friday's sales (the next day):
3a + 7c = 72
we now have a system of equations
2a + 6c = 56
3a + 7c = 72
divide both sides by 2 in the first equation to simplify it
a + 3c = 28
subtract 3c from both sides to solve for a
a = 28 - 3c
plug that into the second equation to remove a variable
3(28-3c) + 7c = 72
84 - 9c + 7c = 72
84 - 2c = 72
subtract 84 from both sides to isolate the variable and its coefficient
-2c = -12
divide both sides by -2 to solve for c
c = 6
a = 28 - 3c
= 28 - 3 * 6
= 10