Random Number Generator and Variance

240 Views Asked by At

Hi Math Stack Exchange Community,

I've been trying to solve this question related to variance and discrete random variables and I couldn't find a way to approach and solve this question. I would be glad if you could help. Thanks in advance.

A random number generator​ (RNG) is designed to generate random numbers from 1 to 8. Let X and Y be the
two numbers that appear when the RNG is run twice.

(a) What is the variance of the random variable 2X - Y?
(b) What is the variance of the random variable X+4Y-3?