Question 157524
The 72 pcs/hr that are produced are NOT scrap
If there is 10% scrap, then 
90% x (production + scrap) = 72 pcs/hr
{{{.9*(72 + s) = 72}}}
{{{72 + s = 80}}}
{{{s = 80 - 72}}}
{{{s = 8}}}pcs/hr
The percent increase in production is
{{{8 / 72 = .1111}}}
or about 11.1%