You know that there are 64 children under 12 and 103 total people. This means that the number of people over the age of 12 has to be (103 - 64). To find the amount of money earned from this group of people, just multiply by the price for people over the age of 12: $45. Thus, one part of your equation has to be (103 - 64)∙45.
<span>The second part of the equation is a bit more difficult. You know that x = the number of children under 3, and those children are free. All we need to find is the number of children between 3 and 12 who have to pay and then multiply by their price: $34. So, just subtract the free children from the total children and multiply by 34: (64 - x)∙34. </span>
<span>Put this all together and you get (64 - x)∙34 + (103 - 64)∙45</span>
