The number of single tickets is x, and we know that a single ticket costs $3. Thus, we can express the cost of x single tickets as
Now we can write an inequality to represent when this expression is less than the cost of a monthly pass, which costs $89. This gives us
To determine which option is less expensive after 25 rides, we can substitute x=25 into the inequality. If the it holds, the single ticket option is less expensive. If not, the monthly option is less expensive.