If labour productivity increased 20%, then the factor would be 1.2 x 120 = 144 manhole covers. In other words, labour productivity has a significant impact on how much of the material is made in the 10 hours. Productivity can be increased by such things as technical innovations to facilitate the manufacturing.
A foundry produces circular utility access hatches (manhole covers). currently, 120 covers are produced in a 10-hour shift. if labor productivity can be increased by 20%, it would then be: