A new piece of tubing should be cut approximately ________% longer than the tube to be replaced.

The correct choice suggests that when cutting a new piece of tubing to replace an old one, it should be approximately 10% longer than the original tube. This additional length accounts for various factors that may arise during installation.

For instance, having slightly more length ensures that there is enough material available to work with when connecting fittings or adjusting the tubing to fit the specific installation requirements. It also allows for any miscalculations that may occur during the cutting process, as well as potential changes in the tubing's position or shape once it is put in place.

This 10% guideline strikes a balance, providing enough extra length without significantly wasting material. In fluid line and fitting applications, optimal tubing lengths are crucial for maintaining efficient flow and preventing leaks, making this principle particularly relevant in practical scenarios.