Answer:
Step-by-step explanation:
The computer fleet represents 100%.
A 5 year rotation plan means that after 5 year you computer fleet must be completed new.
To achieve that cycle, you must replace a 20% every year in order to accomplish the 5-year plan, because 20% + 20% + 20% + 20% + 20% = 100%.
Therefore, the answer is 20%.