# Math Help - picking 2 defective question I cant understand answer

1. ## picking 2 defective question I cant understand answer

Hello

The question is:
In a shipment of 100 televisions, 6 are defective. If a person buys two televisions from that shipment, what is the probability that both are defective?

I calculated 6/100 * 6/100 = 9/2500 but the correct answer is 1/330. how do you arrive at 1/330?

Angus

2. Originally Posted by angypangy
In a shipment of 100 televisions, 6 are defective. If a person buys two televisions from that shipment, what is the probability that both are defective?
I calculated 6/100 * 6/100 = 9/2500 but the correct answer is 1/330. how do you arrive at 1/330?
It should be $\frac{6}{100}\frac{5}{99}$

3. Ah of course. Thanks. I was forgetting that it would be conditional prob.