Final answer:
The total energy requirement for the server farm will double in about 10 years.
Therefore, the correct answer is: option b). about 10 years
Step-by-step explanation:
The rule of 70 tells us that the time it will take for a system or collection to double in size is 70 divided by the percentage growth rate.
In this case, the energy requirements for your server farm grow at a rate of 7% per year.
So, to find out how long it takes for the total energy requirement to double, we can use the rule of 70.
Step 1: Calculate the doubling time by dividing 70 by the growth rate of 7%:
Doubling time = 70 / 7
= 10 years
So, it takes about 10 years for the total energy requirement to double.