If the mean and the variance of a binomial variate X are 1 and 0.75 respectively, then which of the following is true?

A box contains 8 red and N green balls. Two balls are drawn at random from it. If X is the random variable representing the number of green balls drawn and $E(X) = 1.2$, then $N = \ldots$

If a fair coin is tossed 8 times, then the probability of getting at most 2 heads is...

If a random variable $X$ has a probability mass function $P(x) = \begin{cases} kx^2, & \text{for } x = 1, 2, 3, 4 \\ 0, & \text{otherwise} \end{cases}$, then the mean of $X$ is ...