If it took 563 minutes to complete a hospitals first cornea transplant, and the hospital uses a

Question:

If it took 563 minutes to complete a hospital’s first cornea transplant, and the hospital uses a 90% learning rate, what is the cumulative time to complete?
(a) The first 3 transplants?
(b) The first 6 transplants?
(c) The first 8 transplants?
(d) The first 16 transplants?