Answer:
180 orange marbles
Explanation:
the 2 part of the ratio refers to the amount of yellow marbles.
divide amount of yellow marbles by 2 to find the value of one part of the ratio.
120 ÷ 2 = 60 ← value of 1 part of the ratio , then
3 parts = 3 × 60 = 180 ← number of orange marbles