Help need to turn in soon

How is working backward similar to solving an equation?

At store a, erasers are sold individually. the cost y of x erasers is represented by the equation y=0.75x. the costs of erasers at store b are shown in the graph.

Hannah reads at a constant rate of 33 pages every 88 minutes. write an equation that shows the relationship between pp, the number of pages she reads, and mm, the number of minutes she spends reading.