I hope this helps you
cos71=15/P
0.325=15/P
P=46.15
You have 11 items and you need to choose 5 of the 11.
There are 462 ways to choose them.
The formula is :
11! / (5!6!)
n!/(r!(n-r)!)
To solve for 2 variables, you need 2 equations. The best you could do with only one equation would be to find 'a' in terms of 'b'. Just looking it over and without putting pen to paper, it looks to me like one possible solution is [ a = 4, b = 0 ].
