Question 825062
The probability that any one of the 9 printers will not be defective is {{{5/9}}} .
If you pick one that is not defective, you will have 8 printers to choose a second printer from,
and 4 of those are defective, so your chance of picking a second good one is
{{{4/8=1/2}}} .
Multiplying, you find that you would pick 2 good printers
{{{(5/9)(1/2)=5/18}}} of the time.
Your probability of picking 2 good printers from that lot is
{{{highlight(5/18)}}}=0.278 (rounded) or 27.8%.