The probability that both radios are defective =

Explanation:
Here, the total number of radios = 20
The number of defective radios = 6
The number of radios selected at random = 2
P(Selecting first defective radio) =

Now, after selecting first defective radio, total radios left = 20 - 1 = 19
Also, total defective radios = 6 - 1 = 5
P(Selecting second defective radio) =

So, the combined probability of selecting 2 defective radios

Hence, the probability that both radios are defective =
