Answer:
45.136 hours
Explanation:
learning rate = time needed to produce second unit / time needed to produce first unit = 8.8 hours / 10.4 hours = 0.8462 ≈ 85%.
time needed to produce the last 10 units = cumulative time needed to produce 40 units - cumulative time needed to produce 30 units
time needed to produce the last 10 units = 222.872 hours - 177.736 hours = 45.136 hours