We are given the standard length of the metal rods cut by a machine and it is 4.25m. The acceptable deviation is 0.02m.
Roughly, we can state this as L = 4.25 ± 0.02. This means that the length can be anywhere from 4.23m to 4.27m. We can write this inequality as:
But because we need the inequality to be stated in absolute value terms, we write:
When solving for this inequality, we actually go back to the previous inequality, which tells us that we got it correctly.