Probability Question - Express in terms of P

Hi, I am currently stuck on a probabilities question and I was wondering if anyone could help me a bit.

A and B are two events. Suppose that
P(B'|A) = 0.75
P(A'|B) = 0.6
P(A') = 0.4
A' and B' are complementary events of A and B respectively. Let P(B) = p, where 0<p<1.

1.Express P(A' n B) in terms of P
2.Find the value of p
3.Are A and B independent? Explain your answer

I've been on it for two days and I just can't seem to find a solution. Any help would be greatly appreciated. Thanks.

There was a previous question to this, which was "Find P(A n B')", which I have calculated. I feel that it should've helped me answer the "Express P(A' n B) in terms of P" question" but I can't find the connection.