There were some blue, red and green marbles in a jar. 2/9 of them

were blue marbles and 107 of them were green marbles. There were
8 more red marbles than blue marbles. How many marbles were there altogether?

1 answer

so, if there were x marbles to start with, then
2/9 x + 107 + 2/9 x + 8 = x
now just solve for x