Originally Posted by **andy_atw**

I need to know if I am on the right track with this.

A factory has 3 shifts. the shifts produce 1%, 2% and 5% defective items respectively. If all shifts have the same productivity, (1) what percentage of the items produced in a day are defective? (2) what is the probability that the defective items were produced on the third shift?

This is what I came up with:

let n = total number of items produced daily.

each shift produces n/3 items.

we are looking for total (defective/total produced).

=((n/3)(.01+.02+.05))/(n) which equals .03%