Answer:
There is no common difference
Step-by-step explanation:
The first is yes and the second is no
60%
Working
£5:100%
£1:20%
£8:160%
So percentage increase is 60%
The formula for calculating length is:

We can also write

or

Why it does not matter?
Let's assume we have 2 numbers, a and b.
When we perform a subtraction:

, we get another number

When we perform another subtraction:

, we get a number

When we raise

or

to the power of 2, the result is the same,

.