If a certain computer is capable of printing 4700 monthly credit card bills per hour, while a new model is capable of printing at a rate of 6800 per hour, the old model will take approximately how much longer than the new model to print 10000 bills?	Choose the correct choice from the following answers.
A) 19 mins  B) 29 mins  C) 39 mins  D) 38 mins  E) 37 mins
old model's 1 hr work = 4700   new model's 1 hr work = 6800   old model' time taken to print 10000 cards   for 1 hr -- 4700 cards   x   -- 10000= 
<gadget id="calculator">  -- 10000</gadget>
<output>10_000</output>
10000/4700= 100/47   new model' time taken to print 10000 cards   for 1 hr -- 6800 cards   y   -- 10000= 
<gadget id="calculator">  -- 10000</gadget>
<output>10_000</output>
10000/6800= 100/68   x= 10000/4700 = 100/47 = 2 6/47 hr   Difference is   100/47 - 100/68 = 6800 - 4700 /(47*68)   2100/3196 = 0.66 hrs =&gt; 39minutes   Old model ll take 39 minutes longer to print 10000 cards than new model   Ans : 39 mins   ANSWER:39 mins
<result>C</result>
If a certain computer is capable of printing 4700 monthly credit card bills per hour, while a new model is capable of printing at a rate of 6800 per hour, the old model will take approximately how much longer than the new model to print 10000 bills?