1. Solve the equation for n algebraically.
nCn-2 = 10
Would I have to divide the left side by (n)(n)(n-1)(n-2), which would cancel out (n) and (n-2). Im stuck with what to do after that.
2. A pencil case can hold seven pens and eight pencils. Meg chooses either a pen or pencil. Then John is to choose a pen and a pencil. In which case (based on Andrea's initial choice) would John have to have the greater number of choices.
I think Meg's choice would be: 7C1 x 8C0 + 7C0 x 8C1
Then i get stuck on John. Would it be 6C1 x 7C1
Thanks.