The city zoo has different admission for adults and children. When three adults and two children went to the zoo, the bill was $79.21. If two adults and three children got in for $75.49, then what is the price of an adults ticket and what is the price of a child's ticket?
3 a + 2 c = 79.21 multiply by 3
2 a + 3 c = 75.49 multiply by 2
9 a + 6 c = 237.63
4 a + 6 c = 150.98
-------------------------- subtract
5 a = 86.65 etc