Answer: the price of an adult ticket is $11
the price of a child ticket is $11
Step-by-step explanation:
Let x represent the price of an adult ticket.
Let y represent the price of a student ticket.
On the first day of ticket sales the school sold 7 adult tickets and 6 student tickets for a total of $143. This means that
7x + 6y = 143 - - - - - - - - - -1
The school took in $187 on the second day by selling 4 adult tickets and 13 student tickets. This means that
4x + 13y = 187 - - - - - - - - - -2
Multiplying equation 1 by 4 and equation 2 by 7, it becomes
28x + 24y = 572
28x + 91y = 1309
Subtracting
-67y = -737
y = -737/-67 = 11
Substituting y = 11 into equation 1, it becomes
7x + 6×11 = 143
7x + 66 = 143
7x = 143 - 66 = 77
x = 77/7 = 11
