Answer
Find out the after how many rides will the total costs of the two options be the same .
To proof
let us assume that the number of rides is represent by r.
As given
You ride an express bus from the center of town to your street
You have two payment options.
Option A is to buy a monthly pass and pay $0.80 per ride.
Option B is to pay $2.30 per ride.
A monthly pass costs $30.
than the equation is become in the form
30 + 0.80r = 2.30r
30 = 1.5r

r = 20
Therefore after 20 rides the two options be the same.
Hence proved