Online Course Discussion Forum

Need help on winter camp blue Combinatoris p8, p9 and p10

 
 
Picture of Iris Xu
Need help on winter camp blue Combinatoris p8, p9 and p10
by Iris Xu - Monday, 4 January 2021, 7:50 PM
 

thanks!

 
Picture of Charles Zhang
Re: Need help on winter camp blue Combinatoris p8, p9 and p10
by Charles Zhang - Tuesday, 5 January 2021, 8:16 AM
 

For #8:  The Hint is Spot-on.  Remember:

Probability of surviving in spot A_n = n/10 * probability of surviving in spot A_n-1 +

                                                                            (10-n)/10 * probability of surviving in spot A_n+1

And A_5. Hmmm.... It's not leaned in one way or another.


For #9: Casework with number of heads!

For #10: Geometric sequences can be written as a, ar, ar^2, ar^3, ar^4....ar^29.  How can you choose 3 of these such that they are in a geometric sequence.  (This is casework with ratio)


Hope these helped! Might have given away too much.