There are 30 green marbles and the ratio of orange to green is 4/5, so 4/5=orange/green=orange/30.
30 is 6 times 5, so orange=6 times 4=24. There are 24 orange marbles.
Total of orange and green=24+30=54.
40% of the marbles are yellow so 60% are orange/green. Also 60% is 54 marbles.
60% is 60/100=3/5 so 3/5 of the total is 54 marbles, therefore 1/5 is 54/3=18 and 2/5 is the number of yellow marbles=2 times 18=36 yellow marbles.
