All 250 files on Sam's hard drive are infected by either a virus or a worm or both. The number of files that are infected only by a worm is 2.5 times the number of files that are infected by both a virus and a worm. If 50% of the files were not infected by a virus, how many of Sam's files were NOT infected by a worm? Answers
A) 50  B) 70  C) 75  D) 100  E) 125
n(Total) = 250   n(only worm) = 125(50% of total)   n(only worm ) = 2.5 * n(both worm and virus)   So,   n(both worn and virus) = 125/2.5= 
<gadget id="calculator">125/2.5</gadget>
<output>50</output>
50   n(Total)= n(only worm) + n(both worm and virus) + n(only virus)   n(only virus) = 250-125-50= 
<gadget id="calculator">250-125-50</gadget>
<output>75</output>
75   Hence, the files not infected by worm is n(Only virus)= 75   ANSWER :(Option 75)
<result>C</result>
All 250 files on Sam's hard drive are infected by either a virus or a worm or both. The number of files that are infected only by a worm is 2.5 times the number of files that are infected by both a virus and a worm. If 50% of the files were not infected by a virus, how many of Sam's files were NOT infected by a worm?