Question

4.30 The proportion of time Y that an industrial robot is in operation during a 40-hour week is a random variable with probability density function
f(y) = 2y between 0 and 1
0 at elsewhere
from this equation I found
E(Y)= 2/3
E(Y^2)=1/2
V(Y)=1/18
How would I find the V(X) for the next part of the problem
"Profit X for a week is given by X=200Y-60"