question no. 37, 38 and 39 with solution please, thank you

37. R Ltd. has been investigating the time taken to produce one of its products, and found that a 90 percent learning curve appears to be applicable. If the time taken for the unit is 4,000 hours, the total time taken for units 5-8 only is: a. b. 10.368 hours 11.664 hours c. d. e. 12.960 hours 23.328 hours 36.000 hours (cima) 38. A production operation operates on an 85 percent learning curve. It takes 100 hours to produce the first unit in a batch. To produce a 14-unit batch takes: a. 1,400 hours c. 114 hours b. 962 hours d. 754 hours e. 521 hours (cima) 39. Data relating to the production of the first twelve units of a new product are as follows: Time taken to produce the first unit 15 hours Cumulative time taken to produce first 12 units 81 hours The percentage learning effect is closest to a. 45% 70% b. 55% d. 80% e. 90% (cima) VIT