Five machines at a certain factory operate at the same constant rate. If four of these machines, operating simultaneously, take 35 hours to fill a certain production order, how many fewer hours does it take all five machines, operating simultaneously, to fill the same production order?  Pick
A) 3	B) 5	C) 7	D) 16	E) 24
Total work = 4*35 machine hrs   Time taken = 4* 35 /5= 
<gadget id="calculator">4* 35 /5</gadget>
<output>28</output>
&gt; 28 hours...   Thus all five machines, operating simultaneously will take ( 35 - 28 ) 7 hours..   Answer will be (7) 7
<result>C</result>
Five machines at a certain factory operate at the same constant rate. If four of these machines, operating simultaneously, take 35 hours to fill a certain production order, how many fewer hours does it take all five machines, operating simultaneously, to fill the same production order?