Question

it cost $35 for one adult and two children to attend a show. It cost $60 for two adults and three children to attend the same show. How much does it cost one adult to attend the show?

Answer 1

Assume that,
adult = x
child = y

x+2y = 35 (1st equation)
2x+3y = 60 (2nd equation)
x = 35-2y (3rd equation)

Substitute 3 into 2 :

2(35-2y) + 3y =60
70-4y +3y = 60
y = 10

x+2y = 35
x+2(10) =35
x +20 =35
x = 15

One adult = $15