Answer:
25%
Explanation:
If there is 20% scrap, then
80% of (production + scrap) = 72 pcs/hr
Now,
[tex]\frac{80}{100} \times (72+scrap)= 72 pcs/hr\\0.80\times (72+Scrap) = 72 \\ 72+Scrap = \frac{72}{0.80}\\72 + Scrap = 90\\Scrap = 18 pcs /hr[/tex]
The percent increase in labor productivity is, [tex]\frac{18}{72} =0.25[/tex].
Or it can be written as 25% of which would give 80 pieces per hour.