Explanation

To find the fraction of green marbles, we need to calculate the total number of marbles first.

Sara has:

- 5 red marbles

- 3 green marbles

- 2 blue marbles

Total marbles = 5 (red) + 3 (green) + 2 (blue) = 10 marbles

Next, we determine the fraction of green marbles out of the total marbles:

Fraction of green marbles = Number of green marbles / Total number of marbles

Fraction of green marbles = 3 / 10