Q.

The probability, of forming a 12 persons committee from 4 engineers, 2 doctors and 10 professors containing at least 3 engineers and at least 1 doctor, is          [2025]

1 129182  
2 103182  
3 1726  
4 1926  

Ans.

(1)

Total number of ways of selecting 12 people from 4 engineers, 2 doctors and 10 professors = C1216 = 1820.

To determine favourite outcomes:-

To select at least 3 engineers 1 doctor is, we can choose

4 Engineers 2 Doctors 10 Professors Number of ways
3 1 8 C34×C12×C810=360
4 2 6 C44×C22×C610=210
3 2 7 C34×C22×C710=480
4 1 7 C44×C12×C710=240

Total favourable outcomes = 1290

So, required probability =12901820=129182.