learning curve examples

You have explained two examples in your lecture on learning curve (part 2). But I asked you this specifically to know whether I understand them completely or not.

For example 1:
The average time taken by each unit.

First unit—–= 80 hours
Second unit = 55 hours

What is the learning rate?

Output units—-Avg hour per unit—–Total hours
——-1—————–80 hrs (r)————-80 hrs
——-2————–67.5 hrs (r)^1———135 hrs

Since first unit takes 80 hours per unit and second unit takes 55 hours but in total time the two units take (80 + 55) = 135 hours.

learning rate (r) = 67.5 / 80 = 84.375%

For example 2:
The average time taken by each unit.

First unit = 100 hours
Fourth unit = 50 hours

What is the learning rate?

Output units—–Avg hour per unit——Total hours
——–1————–100 hrs (r)————-100 hrs
——–2——————–hrs (r)^1—————-hrs
——–4—————-50 hrs (r)^2———-200 hrs

Since first unit takes 80 hours per unit and second unit takes 55 hours but in total time the two units take (80 + 55) = 135 hours.

learning rate (r) = (50 / 100)^1/2 = 70.7%
learning rate (r) = ^2?(50 / 100) = 70.7%

Both of these approaches give the same answer of 70.7%.

Is that all correct what I have written above?

Thanks for your patience