Math help (1 Viewer)

[Farhanthestudent005]

 

[jimmysmith560]

Would the following working help with (b)(i)?

Let the twins be Aa, Bb, Kk, Dd, Ee, Ff

First choose 3 sets of twins in

Then from each set, there is a choice of choosing either twin.

So total number of ways is

An alternative method is as follows:

Pick 1 person from the 12 possible, then to avoid choosing the person’s twin there are only 10 possibilities to pick the next person and then 8 for the final choice i.e. 12 × 10 × 8 = 960. But this means that if we picked A, B and d then this will also end up giving us d, A and B and all the other permutations of A, B and d.

So to avoid this over counting, the number of possible committees is

 

[Farhanthestudent005]

Thank you very much. I also kind of forgot how to use binomial and normal approximation for a). Is it ok if you could tell me what to do and how to use it?