Solution:
Take x as the number of child tickets sold, and y as the number of adult tickets sold.
so the equations will be:
6.30x+9.60y=1136.40 Equation 1 : Total sale.
x + y = 139 Equation 2: Total amount of tickets sold.
From equation 2, we obtain:
x = 139-y Equation 3
replacing this into equation 1, we get:
applying the distributive property, this is equivalent to:
this is equivalent to:
this is equivalent to:
solving for y, this is equivalent to:
now, replacing this into equation 3, we obtain:
So that, we can conclude that the correct answer is:
the number of child tickets sold is x= 60