s + a = 150 ➡ s = -a + 150
3s + 8a = 1,000
*Substitute the first equation into the 2nd one.
3(-a + 150) + 8a = 1,000
-3a + 450 + 8a = 1,000
5a = 550
a = 110
*110 adult tickets were bought. Now we have to find the amount of student tickets. For that we have to substitute the previous answer into the first equation.
s = -(110) + 150
s = -110 + 150
s = 40
*40 student tickets were bought.
*Double check.
40 + 110 = 150 tickets
3(40) + 8(110)
120 + 880 = 1,000 dollars.
