First, we must find what percent of 7,000 is 160.
To do this, let's do 160/7,000
160/7000 simplified is 4/75.
So, 4 out of every 75 CDs will be defective. If we want to find the probability of them all being affective, we must first do 71/75, because we subtracted the amount of defective CDs from the numerator.
Next week must multiply 71/75*71/75*71/75*71/75*71/75 to get the probability of 5 randomly selected ones being affective.
I got 1804229351/2373046875
If you divide this, you get 0.76030076354, so there is about a 76 percent chance of having all 5 randomly pulled be affective.
.Hope this helped! Comment if you have any questions!!!