there were 350 green leaves on a branch of a maple tree. when 80 yellow leaves fell and 20 green leaves change?

[Sen]

there were 350 green leaves on a branch of a maple tree. when 80 yellow leaves fell and 20 green leaves changed their color to yellow , then the number of yellow leaves became half the number of the green ones. how many leaves of each colour were there on the maple tree at the beginning?