Answer:
280 adult tickets
130 student tickets
190 children tickets
were sold at the concert
Explanation:
Let the number of students be s , adults a and children c
Total 600;
Thus;
a + s + c = 600 •••••••(i)
let us look at revenue
Revenue = number * ticket price
For adults; a * 7 = $7a
For students ; s * $3 = $3s
For children; c * $2 = $2c
Total is 3150
thus;
7a + 3s + 2c = 3150 ••••••••(ii)
150 more adults than students;
a = s + 150 ••••••(iii)
Substitute iii into ii and i
into ii
7(s + 150) + 3s + 2c = 3150
7s + 1050 + 3s + 2c = 3150
9c + 3s = 3150-1050
9c + 3s = 2,100 •••••••(x)
Substitute into i
a + s + c = 600
s + 150 + s + c = 600
2s + c = 600 - 150
2s + c = 450
c = 450 - 2s ••••••(xx)
Now substitute xx into x
9(450-2s) + 3s = 2100
= 4050-18s + 3s = 2100
4050-2100 = 18s - 3s
15s = 1950
s = 1950/15
s = 130
c = 450 -2s
c = 450 - 2(130)
c = 450 - 260
c = 190
a = 150 + s
a = 150 + 130
a = 280