question on conditional probability calculation

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I have an item which is defect or non-defect.

And I will test whether it is defect or not.

P(test defect | defect) = 0.7

P(test nondefect | nondefect) = 0.75

P(defect) =0.05

Then, I will calculate

I) P(test defect)=?

II) P(defect |test defect) = ?

III) P( defect | test non defect) = ?


In order to find these parts, will I calculate following formulas?

I) P(test defect) = P(test defect | defect) * P(defect) + P(test defect | nondefect)* [1- P(defect)]

II) P(defect |test defect) = P(test defect | defect) * P(defect) / P(test defect)

III) P( defect | test non defect) = I have no idea.

Please help me to do this. Thank you.