In a bolt factory, machines A, B and C manufacture respectively 25%, 35% and 40% of the total bolts. Of their output 5, 4 and 2 percent are respectively defective bolts. A bolt is drawn at random from the product. What is the probability that the bolt drawn is defective?

Explanation

To solve the problem, we need to calculate the probability that a randomly drawn bolt is defective. We will use the law of total probability.

### Step 1: Define the events
Let:
- \( A \): the event that a bolt is produced by machine A
- \( B \): the event that a bolt is produced by machine B
- \( C \): the event that a bolt is produced by machine C
- \( D \): the event that a bolt is defective
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