Thread: number of ways an item can be defective

1. number of ways an item can be defective

I have the question
There are 12 ways in which Manufactured item can be a minor defective and 10 ways in which it can be a major defective. In how many ways can 2 major and 2 minor defects occur?
I would of thought to use 12P2 x 10P2 but that gives the completely the wrong answer

2. Originally Posted by renlok
I would of thought to use 12P2 x 10P2 but that gives the completely the wrong answer
Use combinations and not permutations.
$_{12}\mathcal{C}_2=\frac{12\cdot 11}{2}$