An expression to represent this would be 1.40x+8.00=C (C is total cost).
If you had $26.00 you would first spend $8.00 on the entry leaving you with $18.00. Then you would divide the $18 by $1.40 for each ride to get 12.8... It doesn't make sense to go on a fraction of a ride so you just round down to 11 rides