hi im doing a math portfolio and need to find out how to get this answer

Question

im making a friut punch that totals 7 1/2 quarts of juice and i used 31/4 quarts of one type of juice and  1 1/3 quart of another kind of juice and ,w, quarts of another kind of juice ...what is ,w, to make up the toal of 7 1/2 quarts of total juice

Answer 1

Set up an equation that adds up the three different types of juice to equal the 7 1/2 total quarts of juice. 

 

3 1/4 + 1 1/3 + w = 7 1/2

 

find common denominator so you can add 3 1/4 and 1 1/3. So now you have:

 

3 3/12 + 1 4/12 + w = 7 6/12

4 7/12 + w = 7 6/12

 

solve for w. subtract 4 7/12 from 7 6/12. 

 

W=2 11/12