## Omniscience 3 years ago If a random selection is made from 1,2,3,4,5,6 where the digits cannot be repeated, find the probability that the number selected is greater than 4500

1. apple_pi

how many numbers are selected? 4?

2. Omniscience

yeah 4 digits; i forgot to mention that sorry

3. apple_pi

well if > 4500, there are two cases: 1: first number = 4, second = 5 2: first number > 4

4. Omniscience

isnt the first case 4,5 ,6?

5. Ishaan94

2C1*6P4 + 2C1*5P2?

6. Omniscience

nope

7. Ishaan94

Are you sure?

8. Omniscience

yes itcant be that high lol the probability is 2/5 and from what you got is 14440/360

9. Omniscience

wait from what you got is 760/360; still not right

10. IsraelYkb

(12*6)/(6*5*4*3)

11. IsraelYkb

mine 72/360.

12. Omniscience

i got that as well; still not right

13. Ishaan94

I am sorry. I blew it :( First Case. When first digit is greater than 4 i.e {5,6}. 2C1*(5*4*3) Second Case. When first digit is 4, and second is 5. 4*3

14. IsraelYkb

@Omniscience 2/5 is not right?

15. Omniscience

72/360 = 1/5 still not right..

16. Ishaan94

Second Case should be 2*4*3 as the second could be 6 also. I believe I have got the answer.

17. Ishaan94

... second digit* could be ...

18. Omniscience

yes ishaan got it. thanks

all case : |dw:1347236931812:dw|

20. IsraelYkb

|dw:1347266631816:dw|

21. IsraelYkb

2*(12)+120

22. IsraelYkb

I GOT IT!!!!!!!!!!!!!!!!

23. IsraelYkb

144 ways out of 360

why, 2*12?

25. IsraelYkb

oh....|dw:1347267287282:dw| that's why

26. IsraelYkb

that's 1*2*4*3 same as 2*12

oh, yea... i am forget that |4|6|...|...| should can be selected ... lol thanks @IsraelYkb

28. IsraelYkb

and using 5 and 6 it's very easy it's just 2*5*4*3