Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: R

There are no items in this cart.
Continue Shopping
Get instant 20% OFF on Online Material.
coupon code: MOB20 | View Course list

Get extra R 550 off


a lot contains 20 articles.d probability that d lot  contains xactly 2 defective articles is 0.4;and d probability dat it contains exactly  3 defective articles is 0.6.articles r drawn from d lot at random 1 by 1 without replacement until all d defective r found.Wat is d probability dat d testing procedure stops at d twelfth testing?

7 years ago


Answers : (1)


Clearly there are two cases, either the lot as 2 deffective articles or 3 as the sum of probabilities is 1.

Now case 1 : When the lot has 2 defective articles. So we are going to draw one defective article between deaw no 1 to 11th and will draw the second defective article at 12th draw as this will mark the end of our search for this case.

So the probability will be 18/20.17/19 …...9/11.(2/10).1/9 (total 12 draws in which we have taken perfect articles till 10th draw, on 11th we took one defective and on twelth we took another defective)

Now we need to arrange one defective draw in 10 perfect article draws which will be : (11!)/(10!.1!)

Multiply this with the above series, this is result for first case,

Similary for the second case we have : 17/20.16/19.......9/12 . 3/11 . 2/10. 1/9 (i.e. 9 perfect article draws and there on 3 defective draws, now we need to keep the twelth draw at its place and have to permute rest 11 draws in which 9 are perfect draws and 2 are defective so : (11!)/(9!.2!) Multiply this with the second case series.

Add the results of two cases, which will be ur answer. ie:
18/20.17/19 …...9/11.(2/10).1/9[(11!)/(10!.1!)] + 17/20.16/19.......9/12 . 3/11 . 2/10. 1/9[ (11!)/(9!.2!)]
one year ago

Post Your Answer

Other Related Questions on Algebra

please solve all 7 marks question in attached photo
I have solved Q3 here. Please post question one by one.
Harsh Patodia one month ago
how does it implies that a real number is rational if x ½ is rational?
Please put the complete question. Here no reference is given about x.
Harsh Patodia one month ago
What happens to characteristics properties of quadratic equation if instead of x being real variable it is a complex variable properties like sum of roots& product of roots
Posting again as previous answer did not get posted correctly. The properties of roots of quadratic equation remains same even if the roots are not real
Ajay 3 months ago
The dir cosines of two lines are related by l+m+n=0 & a(l)2+b(m2+c(n)2=0 the lines
Represent one in the form of other two. Then make a quadratic and frame a relationship between the other two in order to get the answer
Sourabh Singh 7 months ago
how can we easily integrate trignometric function by parts
You can use the integration by parts for that.Its First Function(Integration of IInd)- [(Integration {differentiation of Ist} {Integration of IInd} ].
Sagar Gupta 11 days ago
i want video for strictly and strictly decreasing function
Google – fNp69step6Q and 28uAm2MG0Mo
Anoopam Mishra one year ago
Can`t understand why my answer was disapproved. Search for `fNp69step6Q` and `28uAm2MG0Mo` on Google. T
Anoopam Mishra one year ago
You’re welcome! After watching the videos please tell me if you liked them.
Anoopam Mishra one year ago
View all Questions »

  • Complete JEE Main/Advanced Course and Test Series
  • OFFERED PRICE: R 15,000
  • View Details
Get extra R 3,750 off

Get extra R 550 off

More Questions On Algebra

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!!
Click Here for details