Answer:
[tex]P(Blue)=0.60[/tex]
Step-by-step explanation:
Probability: [tex]Probability\ of\ an\ event=\frac{favourable\ outcome}{total\ outcome}[/tex]
[tex]Total\ marbles=20\\\\Hence\ total\ outcomes=20\\\\Blue\ marbles=12\\\\Hence\ favourable\ outcomes=12\\\\P(Blue)=\frac{12}{20}\\\\P(Blue)=\frac{2\times 6}{2\times 10}\\\\P(Blue)=\frac{6}{10}\\\\P(Blue)=0.60[/tex]