An electronic assembly consists of two sub-system, say A and B. From previous testing procedures, the following probabilities are assumed to be known.

P(A fails) = 0.2, P(B fails alone) = 0.15, P(A and B fail) = 0.15

Evaluate the following probabilities:

(i)  P(A fails/B has failed)              

(ii)  P (A fails alone)