Answer:
Chris sells 5 tickets and Mary sells 16 tickets
Step-by-step explanation:
System of Equations
To solve the problem we call:
x = number of tickets sold by Chris
y = number of tickets sold by Mary
They sold a total of 21 tickets, thus:
x + y = 21 [1]
Mary sold adult tickets for $6.50 each and Chris sold student tickets for $4.00 each. The total income was:
4x + 6.5y = 124 [2]
Multiplying [1] by -4:
-4x - 4y = -84 [3]
Adding [2] and [3]:
2.5y = 40
Dividing by 2.5:
y = 40/2.5
y = 16
From [1]
x = 21 - 16 = 5
x = 5
Chris sells 5 tickets and Mary sells 16 tickets