The output of a factory was increased by 15% to keep up with rising demand. To handle the holiday rush, this new output was increased by 20%. By approximately what percent would the output now have to be decreased in order to restore the original output?  Pick one:  A) 20 %  B) 27 %  C) 30 %  D) 32 %  E) 79 %

Rationale: the original output increases by 15 % and then 20 % . total % change = a + b + ab / 100 total % change = 15 + 20 + 15 * 20 / 100 = 38 % now , you want to change it to 0 , so , 0 = 38 + x + 38 x / 100 x = - 38 ( 100 ) / 138 = 27 % approximately answer is b
Answer: B