Answer:
42 green marbles
Explanation:
sum the parts of the ratio, 7 + 2 = 9 parts
Divide the number of marbles by 9 to find the value of one part of the ratio.
54 ÷ 9 = 6 ← value of 1 part of the ratio , then
7 parts = 7 × 6 = 42 ← number of green marbles