Answer:
(5,15)
Explanation:
We know that 225 = 15a + 10c, and he purchased a total of 20 tickets, so
a + c = 20, using this, we know that c = 20 - a, we can substitute this for c in 225 = 15a + 10c to get:
225 = 15a + 10(20 - a) =
225 = 15a + 200 - 10a
225 = 5a + 200
25 = 5a
a = 5
Now we substitute 5 for a:
225 = 15a + 10c
225 = 15(5) + 10c
225 = 75 + 10c
150 = 10c
c = 15
so a = 5 and c = 15, the solution is (5,15)
P.S. I'm the guy who did your other question