A committee is reviewing a total of 20x black-and-white films and 4y color films for a festival. If the committee selects y/x% of the black-and-white films and all of the color films, what fraction of the selected films are in color?
Choose the correct choice from the following options:
A) 26/21 B) 28/21 C) 20/21 D) 40/21 E) 60/21
Say x=y=10. In this case we would have:   20x=200 black-and-white films;   4y=40 color films.   y/x%=10/10= 
<gadget id="calculator">10/10</gadget>
<output>1</output>
1% of the black-and-white films, so 2 black-and-white films and all 40 color films, thus total of 42 films were selected.   Color films thus compose 40/42=20/21 of the selected films.   Answer: 20/21
<result>C</result>
A committee is reviewing a total of 20x black-and-white films and 4y color films for a festival. If the committee selects y/x% of the black-and-white films and all of the color films, what fraction of the selected films are in color?