Does rebecca burn more than 400 calories per hour? explain

               t = 30a  +  150 . 

' t ' is the total cost of treatment. 
' a ' is the number of appointments. 
The $150 is paid only once. 

I hope Pedro gets better fast.  Poor little guy.


Oh, I see.
Now you're saying that she pays the $150 at every appointment.

So the equation is actually

                         t = 180a