elementary variance/econ q

[lifes3ps]

havent taken probability for 2 years so things have slipped my mind.
Q=100-2P+0.5T, P=10 (nu)T=2.

first part was to find E(PQ). found to be 810, right?

i know Var=E((PQ)^2)-E(PQ)^2, just need helping finding where to put P^2Q^2

Var(PQ)=?

[djames]

[ QUOTE ]
havent taken probability for 2 years so things have slipped my mind.
Q=100-2P+0.5T, P=10 (nu)T=2.

[/ QUOTE ]

Are you saying P and T are constants? If so, then Q is also a constant (81). So PQ is a constant (810). Then E[PQ] = 810 and VAR[PQ] = 0. Do you really mean to write that P & T are constants?

[lifes3ps]

T is a random variable with mean 2 and var(10)
p in this case is constsant