Question

Thirty tickets were sold for a concert, some at 60 cents and the rest at $1. If the total raised was $22, how many had the cheaper tickets?

Answer 1

let y be the number of tickets sold at $1.00

Eqn 1
x+y=30

Eqn 2
0.6x + 1.0y = 22

y = 30-x
substitute y into 2nd equation

0.6x + 1.0(30-x) = 22
0.6x + 30 - x = 22
-0.4x + 30 = 22
0.4x = 8
x = 8/0.4=20

substitute x into eqn 1
20 + y = 30
y = 10