UPSB v3 Archive | Teach me math

So, I need to know how to calculate something. Let me explain.

So there's teams and every player in those team gets points in this game as long as he played in 30% of the matches the team played.
Let's say player A, B and C do 50 matches. They all have 100% of the matches played, they all get points.
Now D enters the team and he wants points so he plays with A and B. I know that he needs around 25 matches to get 33.3% of the games played.
Now C has 66.6% played, D has 33.3% played and A & B both have 100% played. 75 matches are played.

This is all easy so far because D had 0 matches when he joined the team and I can calculate this easy but now comes the scenario where my brain shuts down:

A, B and C decide to play more matches. They play 18 more matches. The team has now 93 matches played and with 25 matches D is below the 30% requirement.

How many matches does D have to play with his mates until he reaches the 30% he needs and how do I calculate this number.

Because the number of matches increases, with every match the amount of matches D needs to gain percentage gets bigger (I think) and this where I'm missing math knowledge because I rather spun pens in class.

Halp.

UPSB v3

Off-topic / Teach me math