number of regular tickets sold is 40
Step-by-step explanation:
Total movie tickets = 90
Earnings from the 90 tickets = $560
cost for matinee admission = $5
let the number of matinee admission tickets = m
cost for students admission = $6
let the number of students admission = s
cost for regular admission = $7
let the number of regular admission = r
$5(m) + $6(s) + $7(r) = Total earnings from the sales of all tickets
5m + 6s + 7r = 560 ...(1)
m + s + r = total tickets
m + s + r = 90 ...(2)
Twice as many regular tickets were sold as matinee tickets:
r = 2(m)
r = 2m ...(3)
substitute for r in equation (1) and (2):
5m + 6s + 7(2m) = 560
5m + 6s + 14m = 560
19m + 6s = 560 ...(*1)
m + s + 2m = 90
3m + s = 90 ...(*2)
From (*2), we will make s the subject of formula:
s = 90 - 3m
substitute for s in (*1):
19m + 6(90 - 3m) = 560
19m + 540 - 18m = 560
m + 540 = 560
m = 560 - 540
m = 20
substitute for m in (3):
r = 2(20)
r = 40
s = 90 - 3m
s = 90 - 3(20)
s = 90 - 60
s = 30
Hence, number of regular tickets sold is 40