[APT]

I have some questions regarding winning %.
Question 1
Team A is .600 against .500 team.
Team B is .400 against .500 team.

What is Team A's winning% against Team B?

Question 2

Team A is .550 against average .450 teams.
What is Team A's winning % against .500 teams.

I have been using simple methods for both questions.
Question 1 .600-.400+.500=.700
Question 2 .550+.450-.500=.500

However I have been feeling it is not accurate.
Is there any better methods for these question?

Thanks.