Over the course of a year, a certain microbrewery increased its beer output by 70 percent. At the same time, it decreased its total working hours by 20 percent. By what percent did this factory increase its output per hour?	Choose the correct option:  A) 50%  B) 90%  C) 112.5%  D) 210%  E) 212.5%
Let's take the original output to be 100 and the new output to be 170% or 170.   Let's take the original work hours to be 100 hours and the new work hours to be 80% or 80 hours.   The old output per work hour = 100/100 hours or 1.   The new output per work hour = 170/80 or 2.125. So the resulting increase is actually new minus old or 1.125 or 112.5%.   112.5%hoice 112.5%
<result>C</result>
Over the course of a year, a certain microbrewery increased its beer output by 70 percent. At the same time, it decreased its total working hours by 20 percent. By what percent did this factory increase its output per hour?