Need help on maths foundation question Gcse

Question:

A bag contains 35 balls.
Each ball is either red or green.
The ratio of red balls to green balls is 3:2.

Work out the smallest number of balls of each colour that have to be added to the bag so that the ratio of red balls to green balls becomes 7:3.

Could someone please explain how you got the answer and the process? Thank you.

Read the rules and stop posting questions with no attempt

These are my mock questions which i have attempted, however I seem to have made a mistake somewhere, thus I want to figure out where I went wrong.

R:G
3:2

LCM of 3 and 2 is 6 so

Number of red balls added to the bag = 6
Number of green balls added to the bag = 6

Question:

A bag contains 35 balls.
Each ball is either red or green.
The ratio of red balls to green balls is 3:2.

Work out the smallest number of balls of each colour that have to be added to the bag so that the ratio of red balls to green balls becomes 7:3.

Could someone please explain how you got the answer and the process? Thank you.