Final answer:
To find the number of red marbles, set up a proportion using the given ratio. The number of red marbles is 82.
Step-by-step explanation:
To find the number of red marbles, we can set up a proportion using the given ratio. If there are 2 green marbles for every 3 red marbles, then the ratio of green to red is 2:3. We can set up the equation:
2/3 = 55/x
Cross multiplying, we get:
2x = 3 * 55
2x = 165
x = 165/2
x = 82.5
Since we can't have a partial number of marbles, the number of red marbles is 82.