Creating systems in context

Courtney walked from her house to the beach at a constant speed of $4$‍ kilometers per hour, and then walked from the beach to the park at a constant speed of $5$‍ kilometers per hour. The entire walk took $2$‍ hours and the total distance Courtney walked was $8$‍ kilometers.

Let $b$‍ be the number of hours it took Courtney to walk from her house to the beach, and $p$‍ the number of hours it took her to walk from the beach to the park.