If `2lamda` is the number of ways of selecting 3 member subset of {1,2,3, . .,29}, so that the number form of a GP with integer common ratio, then find the value of `lamda`

Answer

6

Explanation

`2lamda`=Number of selecting 3 member subsets of {1,2,3, . . ,29}
which are in
GP with common raio (2 or 3 or 4 or 5).
`=[29/2^(2)]+[29/3^(2)]+[29/4^(2)]+[29/5^(2)]`
`=7+3+1+1=13`
`thereforelamda=6`