Question

I attach need help # 72
Thanks

Answer 1

How many total ways can you arrange four different people in a row?

Answer 2

There are a few ways to think about this problem. The "intuitive" way is to say, "it's ½ chance of being in the first half or the second half"

maybe a better way is to count the different ways 4 people can be picked (when order matters). It is 4! or 24 different ways
say you are first. How many of those 24 have you first? the other 3 people will be in positions 2,3,4 and there are 3! ways to pick them. that is 3*2= 6
And how many of the 24 have you in 2nd place? same idea: the other3 are in positions 1,3,4, and again 3! ways: another 6
(or you can list out all 24 ways of ordering ABCD and count up those that have A (you) in the first or second slot).
However you do it, you get 12 out of 24 have you 1st or 2nd.
12/24 = ½

Answer 3

thanks phi

Answer 4

can you help me more

Answer 5

I need help number 18 & 19

Answer 6

can you help me more