Question 411215
There is no formula. However you'll get a system of equations which will eventually reduce to one single-variable equation that is easy to solve.


We can let {{{a}}} be the cost of an adult ticket and {{{c}}} be the cost of a child's ticket. Therefore {{{8a + 2c = 132}}}. Also, the child's ticket is $4 less than an adult's ticket so {{{c = a - 4}}}. We can substitute {{{c}}} into the first equation to get


{{{8a + 2(a-4) = 132}}}, from here you can solve for a, then plug your result into {{{c = a-4}}} to find c.