Yellow balls account for 56+4 80 = 3 4 = 75% of the total.
A: The percentages of yellow balls and blue balls in the box are 75% and 25% respectively.
(2) The ratio of labeled ball is1012 = 56;
The number of yellow balls is:
80÷ 5 6 × 3 4 ,
=80× 6 5 × 3 4 ,
=72 (pieces);
There are 72 yellow balls in the box.