Answer:
She has 15 more purple rocks than blue.
Step-by-step explanation:
purple= 2/3 of all rocks
blue= 3/4 of all rocks that aren't purple
silver= 3 (or 1/4 of all rocks that aren't purple)
if 3 (silver) is 1/4 of all rocks that aren't purple, blue (3/4) is 3x3=9
if purple is 2/3 of all rocks, blue and silver are 1/3 of all rocks
so 1/3 of all rocks would be 9+3=12
if 1/3=12, then 2/3 (purple)=24
-----
At this point:
purple=24
blue=9
silver=3
-----
purple (24) - blue (9) =15
She has 15 more purple rocks than she does blue.
