please give the answer in correct way show the working how they get answer step by step please because i do not understand this question show working all thank you so much please answer all thank you again please tell me what chapter is this

4. If P(A andB) ? 0.4andP(B) ? 0.8,FindP(A | B)

5. If P(A ) ? 0.3,P(B) ? 0.7andP(AandB) ? 0.21, are A and B independent?

6.Each salesperson at Insurance Agency is rated either below average, average, or above average with respect to sales ability. Each salesperson also is rated with respect to his or her potential for advancement?either fair, good, or excellent. These traits for the 500 salespeople were cross-classified into the following table.

Potential for Advancement Sales Ability Fair Good Excellent Below average Average Above average