Question 818721
In a bag of chips 4/7 are red, 1/3 are blue and the rest are yellow. What fraction of the chips are yellow?If there are are 12 yellow chips, then how many chips are there in all?
Given:
bag of chips = 100% or the total number of chips
red = 4/7
blue = 1/3
yellow = 12 chips
Solution:
red + blue + yellow = 1
-
4/7 + 1/3 + yellow = 1
-
yellow = 1 - 4/7 + 1/3 LCD= 21
-
yellow = (21-12-7)/21
-
yellow = 2/21 
yellow = 12 chips 

Let x = total number of chips
Ratio:
{{{ 12/x=2/21 }}}
{{{ 2x=252 }}}
{{{ x=126}}}
{{{ Total Chips = 126 }}}
R=red chips  
{{{ R/126=4/7}}}
{{{ 7R=504}}}
{{{ R=72}}}
B=blue chips
{{{ B/126 = 1/3 }}}
{{{ 3B=126}}}
{{{ B=42}}}

FINAL ANSWER:
yellow = 2/21 in fraction
{{{ Total Chips = 126 }}}
{{{ Red chips=72}}}
{{{ Blue chips=42}}}