Time and work are two important topics that are talked about in Chapter 13. Work Done is the time it took to do the work times the rate of work. Efficiency: If the amount of work done stays the same, it’s the opposite of how long it takes. Pipes and Cisterns: There are two kinds of pipes: those that go in and those that go out. Rate of Filling: This is how fast the pipes are being filled. With the help of RS Aggarwal Class 8 solutions of chapter 13 time and work, students can easily understand all of these important topics.