Answer: 0.8 or 80%
Step-by-step explanation:
First find the total number of marbles:
10 + 15 + 25 = 50 marbles total
To find the number of marbles that are not black:
15 + 25 = 40 marbles that are not black
Set up ratio:
[tex]\frac{40}{50}[/tex] = 0.8 or 80%
