You have a bag which contains only red and green marbles. In this bag with x^2+5 marbles total, x+1 are red. Also, x-3 marbles have a scratch on them. The probability of drawing a red marble from the original bag is equal to that of drawing a marble with a scratch from the marbles left in the bag after twenty scratch-free marbles are taken out of the full bag. How many marbles were originally in the bag?

It's 30, not 50, liar!

its 30 liar

its 30

The answer's freaking 30

it's 30

30!!!!

the answer is 30. :/

It is 30

ok it's 30

Actually, it's 30. I checked on AoPS.