60 people will be attending a presentation. 60% of the memos are blue, 20% are red, 15% are green and 5% are yellow. how many green memos do you need to print?

Do the easiest percentages first:For me its this order to figure it out,
20% of 60 is 12 -double 10%-
5% of 60 is 3 -half of 10%-
15% of 60 is 9 - 10% + 5%-
60% of 60 is 36 -10% x 6-
Add all these together so 12+3+9+36 =60 so he doesn't need to print anymore double check this though!!
 

Enough for the people that are attending

Best answer that i found on yahoo ok   set :   x= length of 2nd piece in cm  x- 3= length of 1st piece in cm  x-4= length of 3rd piece in cm  then since you know they all came from the 20 cm ribbon you add them together and set them equal to 20x+ x-3 +x-4 = 20  3x - 7= 20  3x= 27  x= 9  the shortest piece is the third piece which is x- 4  x-4  9-4 = 5  the length of the smallest piece is 5 cm.  the other lengths are  9 cm  6 cm