How many wins do I need to get from Iron 2 to Silver?

With a 55% win rate, you need to play 240 games, win 132 of them and lose 108.

With a 60% win rate, you need to play 120 games, win 72 of them and lose 48.

With a 65% win rate, you need to play 80 games, win 52 of them and lose 28.

With a 70% win rate, you need to play 60 games, win 42 of them and lose 18.