First, let's calculate the total number of items:
[tex]12+12+11+1=36[/tex]The ratio of books to marbles is calculated by dividing the number of books by the number of marbles:
[tex]ratio=\frac{books}{\text{marbles}}=\frac{11}{12}[/tex]The ratio of DVD's to the total number of items is:
[tex]\text{ratio}=\frac{\text{dvds}}{\text{total}}=\frac{12}{36}=\frac{1}{3}[/tex]The percentage of dvd's from the total is:
[tex]\frac{1}{3}=0.3333=33.33\text{\%}[/tex]