Counting, Probability, Trees, etc in Discrete Math
Sorry for so many questions today guys. But this set will be last set for this week.
Have some probability problems I'm doing in discrete math. I have done most of them but have trouble on starting for some of them and want to check answers on some as well.
Here I go:
Ok for problem 8:
there are 36 possible outcomes
e isn't a trick question is it? it's basically the same as a thru d correct?
i think i have this question done correctly
Problem 9: should be number of multiples of 7 plus multiples of 3 for 5 digits minus number of multiples for 21. so i think i have this done correctly
Problem 10 is what I'm having trouble with. Seems like there are many ways total and I was going to use the probability tree but it doesn't work as well as it would on problem 11.
Problem 11: used tree, got 88888 different pins.
Haven't started 13..but should be similar to 12...no?
14. I used a formula. P(n,r) = n(n-1)(n-2)...(n-r+1)
i set the equation as P(n,5) = (n-5+1) then n-6=2027400
got n as 2027406 and used that for (2027406)!/(5!*2027401!)
Any input would greatly be appreciated, thanks for you help again!