Answer:
4/7.
Step-by-step explanation:
This the question in which marbles have to be taken out of a bag. Odds in another word for probability.
Total number of marbles in the bag = 2 Blue + 1 Green + 4 Red = 7 marbles.
Required marbles = 3 red marbles.
Therefore:
P (a red marble is selected in the first attempt) = Red Marbles / Total Marbles.
P (a red marble is selected in the first attempt) = 4/7.
Therefore, the correct answer is 4/7!!!
