Bunuel wrote:

Tough and Tricky questions: Percents.

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?

A) 50%

B) 90%

C) 112.5%

D) 210%

E) 212.5%

Kudos for a correct solution.Source: Chili Hot GMAT

Above poster is right; wording can be tricky. I finally just wrote out the equation.

Output per hour =\(\frac{TotalOutput}{TotalHours}\)

Let original total output = 100

Let original total hours = 10

Original output per hour: \(\frac{100}{10}=

10\)

Total output increases by 70%; new output = 170

Total hours decrease by 20 percent; new hrs = 8

New output per hour: \(\frac{170}{8} = 21.25\)

Percent increase:

\(\frac{Old-New}{Old} * 100 =\)

\(\frac{(21.25-10)}{10} * 100 =\)

\((\frac{11.25}{10}=1.125 * 100= 112.5\) percent

Answer C

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