a group of 5 people is to be chosen from eight people:
alex betty chris declan emma fui greg and hanna.
If each of the possible groups are equally likely what is the probability that the chosen group will contain greg or hanna?

Question

a group of 5 people is to be chosen from eight people: 
alex betty chris declan emma fui greg and hanna. 
If each of the possible groups are equally likely what is the probability that the chosen group will contain greg or hanna?

anonymous · Answer

2/8?

anonymous · Answer

nah that would be correct if it was choosing from the 8, but its using combinations, because theres many different combinations of a group of 5 using 8 people if you know what i mean :) thanks anyway

anonymous · Answer

um ok sorry :) I'm not really sure :)

anonymous · Answer

thats okay thanks for trying!

anonymous · Answer

haha I've never been very good with those types of problems :)

anonymous · Answer

Is it possible to have greg and hanna both in a single group?

anonymous · Answer

I think it might be.....

anonymous · Answer

hmm yeah i would say it would be possible because its asking greg or hanna :)

anonymous · Answer

$$2\over 8$$ as greg and hanna are 2 ppl out of 8 ppl

anonymous · Answer

Sample spaces= 2/8
favorable outcome= 2/8

anonymous · Answer

yeah but its not out of 8 people, you have to use combinations because its making a group of 5 and there is 8nCr5 ways of making 5 groups of people D:

dumbcow · Answer

look at case where neither greg nor hannah is chosen
then subtract that from 1 to obtain compliment
$$\rightarrow P = 1-\frac{6C5}{8C5}$$

anonymous · Answer

@dumbcow  u r right!

anonymous · Answer

yep @dumbcow is right.

anonymous · Answer

yep that is the answer in the back of my book thankyou dumbcow! :)

dumbcow · Answer

welcome :)