matrices are a bitch
help would be nice

a total of twelve thousand passengers normally ride the greenline of the MBTA during the morning rush hour. The token prices for a ride 25 cent child under 12, adult=1 and senior=50cents. revenue=10,700. price raise 35 child, 1.50=adult and 50cent=senior and revenue would be 15,820. how many riders in each category normally ride the green line during the morning hour

anyone know how to do this
i have the
.25x+1y+.50z=10700 and .35x+1.50y+.50z=15820
but i dont know what to do after