Machines A, B and C make 50%, 30% and 20% of a factory's bolts, and 1%, 2% and 3% of their bolts are faulty. A bolt picked at random is faulty. What is the probability that machine C made it?

\frac{3}{100}

Correct answerYour answer

\frac{1}{5}

Correct answerYour answer

\frac{1}{3}

Correct answerYour answer

\frac{6}{17}

Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer D

Correct answer: D

Worth noting

$\frac{1}{5}$ is C's share of all bolts; among faulty bolts its share is larger, as its fault rate is highest.

Ten questions from Conditional Probability & Bayes' Theorem, at your own pace.

Ten questions from Conditional Probability & Bayes' Theorem, at your own pace.

Explanation