Question

Cinderella ordered different colored fabrics to make a new dress for the upcoming ball. 20% were blue, 1 10 were white, 40% were silver, and the 9 were gold. Determine the number of white fabrics that were ordered for Cinderella’s dress.

Answer 1

We know that
20% --------------> were blue
1/10---> 0.10----> 10%-------------->  were white
40% ---------------> were silver

and 
9 ---------> were gold
so
gold=100%-(20%+10%+40%)-------> 100%-70%------> 30%

30% ---------------------> is equal to 9
10% (were white)-------> X
X=10%*9/30%------> x=3

the answer is
3