Statistics 2... help plz

number 9

Start by finding the mean and variance of one observation.

Then since the observations are independent, all you need to is add the 3 means and add the 3 variances, to find the mean and variances of the required distribution.

thanks.. i tried doing it but i didnt get the answer.
my answer for mean is 13/8 but the answer is 51/8
i didnt bother doing variance because my mean was wrong

The mean is $\displaystyle \sum xP(X=x)$ so you did something wrong for one of them (or all of them?). It should be 17/8.

i got 17/8 but the answers in the book is different