let's take admission fee= z
8z+11z=17.50+21.25
19z=38.75
z=38.25/19
z=2.4 (aprox)
Or In case of Kiara 17.50 amount paid in 8 rides
.so 1 ride=17.50/8
=2.1875
same In case of mia
so 1 ride=21.25/11
=1.9318.
but, they are not match so there is problem in your Questions.