At an international conference, “Red” world countries and “Blue” world countries are the only participants. The ratio of “Red” world participants to “Blue” world participants is 5:5. If one-third of “Red” world participants are left-handed and two-thirds of “Blue” world participants are left-handed, then what is the fraction of the participants who are left-handed?	Pick.
A) 1/4	B) 1/8	C) 1/6	D) 1/2	E) 1
Red: Blue = 5:5   Let Red = 5x and Blue = 5x   1/3 of Red are left handed =&gt; 1/3 * 5x = 5x/3 Red left handed   2/3 of Blue are left handed =&gt; 2/3 *5x = 10x/3 blue left handed   fraction of participants who are left handed = total left handed/ total participants = (red left handed + blue left handed)/total participants = (5x/3 + 10x/3)/(5x+5x) = (15x/30x) = 1/2   Answer : 1/2
<result>D</result>
At an international conference, “Red” world countries and “Blue” world countries are the only participants. The ratio of “Red” world participants to “Blue” world participants is 5:5. If one-third of “Red” world participants are left-handed and two-thirds of “Blue” world participants are left-handed, then what is the fraction of the participants who are left-handed?