Answer: The number of $12 tickets sold is 120
Step-by-step explanation: The $12 tickets shall be represented by A while the $15 tickets shall be represented by B. That means from the information provided, A + B = 300 since a total of 300 tickets were sold in all.
Also the total sales from all tickets amounted to $4140. This too can b expressed as 12A + 15B = 4140
So we now have a pair of simultaneous equations which are
A + B = 300 --------(1)
12A + 15B = 4140 --------(2)
From equation (1), A = 300 - B
We now substitute for the value of A into equation (2)
12(300 - B) + 15B = 4140
3600 - 12B + 15B = 4140
We collect like terms and we now have
15B - 12B = 4140 - 3600
3B = 540
Divide both sides of the equation by 3
B = 180
We can now calculate for the value of A. Substitute for the value of B into equation (1)
A + 180 = 300
Subtract 180 from both sides of the equation
A = 120.
The $12 tickets were represented by A. That means the $12 tickets sold were 120 pieces.
