Question

Let x1 and x2 be two independent random variables with variances var(x 1) = k, var(x2) = 2. If the variance of y = 3x2 x1 is 25, then find k.

Answer 1

Answer:

Actually, it's not x1 and x2. Its 1x and 2x.

Answer 2

Answer:

7

Step-by-step explanation:

Y=3(X2)-(X1)

Var(Y)=9Var(X2)+Var(X1)

25=9*2+k

k=25-18=7