1 The workload of filling a pool of water can be regarded as 1.
2 The working rate of water inlet pipe is 1/6.
The working rate of outlet pipe is 1/8.
Assuming that the pool can be filled after x hours, the water inlet of the water inlet pipe is x/6 and the water outlet pipe is x/8.
5 The equal relation is water inflow x/6-x/8= 1.