For the rendom variable X with Type I Negative Binomial Distribution with k=1 and p=0.6, the mean is k/p and variance kq/p. But in the solution a different answer is given. Mean is given as 5/3 and variance 10/9. The mean calculation gives the answer 5/3. But the variance is 1*(1-.6)/.6=0.4/0.6=2/3. Please guide where I have gone wrong in calculating the variance.
