## anonymous 4 years ago You have 4 math books, 3 english books, and six science books. If you select books at random what is the probability of picking 3 english books?

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1. Ganpat

how many books u have ??

2. Ganpat

@madison712 : lets do it together.. hope u dont mind..

3. anonymous

may be 13 :/

4. Ganpat

add all them together.. you will get total number of books..

5. Ganpat

you have total of 6+4+3 = 13 books.. now, picking book and it shd be English.. so u have 3 English books.. So the probability would be 13C3...

6. anonymous

even i think you are right :)

7. amistre64

probabilities aint greater than 1

8. amistre64

i think a hypergeometric probability might be more condusive

9. amistre64

$\large\frac{\binom{M}{k}\binom{N-M}{n-k}}{\binom{N}{n}}$

10. Ganpat

oh sorry.. small mistake..

11. Ganpat

it should be 3/13...

12. Ganpat

@amistre64 : ?? what say ?

13. amistre64

or one way of looking at it might be if we put all 13 books into a box; the probability of picking an E in the first go around is: 3/13 out of the remaining 12 books ; the probability of picking an E in the 2nd go around is: 2/12 out of the remaining 11 books ; the probability of picking an E in the 3rd go around is: 1/11 P(A and B and C) = P(A) * P(B) * P(C)

14. Ganpat

hmmm, agree.. i thought, just one book.. thnx !!!

15. amistre64

youre welcome