you have a container full of rum

you take a scoop out and replace it with water to equal the original amount

its now part water part rum

then you take the same scoop size out of the mixture

replace with water again to equal the original amount

now the container is 50% water 50% rum.

what is the size of the scoop?

ok you can assume the original is 100oz and when you take the 2nd scoop out its mixed with rum an water dependending on the size,

please help me ive been racking my brain for days on this problem.