Can you show me how to properly set this up in excel, the formula to calculate and the answer?

The probabilities shown in a table with two rows, A1 and A2 and two columns, B1 and B2 , are as follows: P(A1 and B1) = .10, and P(A1 and B2) = .30, P(A2 and B1) = .05, and P(A2 and B2) = .55. Then P(A1|B2), calculated up to two decimals, is

a..33

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