Chapter 13 – Time and Work– R S Aggarwal Solutions for class 8
- If a person A completes a work in n days then, work done by A in 1 day is (1/n) part of the work
- If a person A completes (1/n) part of work in one day then, A will take n days to finish the work.
Rules for problems on pipes and cistern
Rule1: Suppose a pipe fills a tank in n hours. Then, a part of the tank filled in 1 hour = 1/n which means that work done by the inlet in 1 hour is 1/n
Rule2: Suppose an outlet empties a full tank in m hours. Then, a part of the tank emptied in 1 hour = 1/m which means that work done by the outlet in 1 hour is -1/m