Hi, I'm having some problems with a few questions. I'm not cheating because we are given the answers and the work is not for marks. Please see Attached document Numbers

Section A: 5

Section B: 6, 8,9

Please help :/

Printable View

- Feb 17th 2013, 10:56 AMBenja303Help with combinations Etc.
Hi, I'm having some problems with a few questions. I'm not cheating because we are given the answers and the work is not for marks. Please see Attached document Numbers

Section A: 5

Section B: 6, 8,9

Please help :/ - Feb 17th 2013, 03:59 PMMrdavid445Re: Help with combinations Etc.
5 A) I'm not sure if I'm seeing correctly, but I think the top part of the summation is a 6? If so, it's just 2^2+2^3+2^4+2^5+2^6=124

8 B) Use Binomial-theorem

9 B) Let the first term be x and the common ratio be y:

Second term= xy

Third term= xy^2

...

Fifth term=xy^4

We know x=18, so 18(y^4)=32/9

And you can use that to find y

And we know 8th term is x(y^7), and knowing x and y, we can get an answer.