Answer:
Adult Ticket: £7
Child Ticket: £2
Step-by-step explanation:
Let the cost of 1 child ticket be c, adult ticket be a.
[tex]2a + 3c = 20 \\ \\ a + 4c = 15 \\ a = 15 - 4c \\ \\ 2(15 - 4c) + 3c = 2 0 \\ 5c = 10 \\ c = 2 \\ \\ a = 15 - 4(2) \\ a = 7[/tex]
