Distribution

1a. A jar contains 5 red discs, 10 blue discs and m green discs. A disc is selected at random and replaced. This process is performed four times. Write down the probability that the first disc selected is red.

Svar: total discs= 15+m

$\frac{5}{15+m}$

1b. Let X be the number of red discs selected. Find the smallest value of m for which Var(X)<0,6