Please help me I suck at geometry

Mr and mrs smith buy tickets for themselves and their four children. the cost of an adult ticket is ? 6 more than the adult ticket. the total cost of the six tickets is ? 40.50 work out the cost of an adult ticket. in your working let c be the cost of the child ticket and a be the cost of the adult ticket.

Aboat costs 19200 and decreases in value by 12% per year. how much will it cost in 5 years

Which of the following is an example of a rational number? a. π b. √ 9 c. √ 8 d. 3.8362319