Answer: The required value of 'w' is 5 units.
Step-by-step explanation: We are given the following formula:

We are given to find 'w' in units given that P = 30 units and l = 10 units.
Substituting the values of 'P' and 'l' in equation (i), we get

Thus, the required value of 'w' is 5 units.