<PRE><B>Question 616992</B>
Locker comb
The numbers of the lock is 0 to 39 with 3 combinations.
??? 
1. How many combinations are possible on your locker?::: 40C3 = 9880
------------------------------
2. what is the probability that choosing a combination at random would work to open your locker?::: 1/9880
----------------------------------
3. suppose u remember one of the numb is 14 what is the prob to open the locker
Ans: 
# of ways to succeed: 
3 ways to place the 14
39C2 = 741 ways to pick the other 2 numbers
2 way to place the other 2 numbers
---Total # of ways to succeed: 3*741*2 = 4446
Probability of opening if one # is know: 4446/9880 = 
-----------------------------------
4 if u remember that the 1st numb is one digit the 2nd numb is in the teens and the last is in the thirties
# of ways to succeed: 10*10*10 = 1000
Prob = 1000/9880
----------------------------------
5 what is the prob that u can open the locker?
Under wha condition?
-------------------------------
Cheers,
Stan H.
</PRE>