Circuits, what am I doing wrong

[kliker]

Homework Statement

[PLAIN]http://img258.imageshack.us/img258/9067/39943009.png

given this circuit if each of the resistors may consume maximum power = 24 W without overheating, find the maximum power that the circuit can consume

Homework Equations

_{P = I*V
V=I*R}

The Attempt at a Solution

ok the first two are in parallel, so i found the resistance of both, which is 3/2, then we have two resistors in series and I found the total resistance which is 3/2 + 3 = 9/2

before doing this i found the I(total)

which is _{P = I*V => 24 = I^2*3 => I = +/- 4}

having the I total and the total resistance I said

_{P = I^2*R = 16*9/2 = 72 W}

but the book says 36, what am I doing wrong?

Thanks

 

[irycio]

You are wrong with your first statement. You said that the max. power consumption of a SINGLE resistor is 24W, but calculated a power consumption of a whole circuit.

My idea is as it follows:
1. P=I^2*R. Obviously the currency flowing through the resistor on the right will be the, khem, biggest (dunno what's the proper word in english :P). You should assume that it is 24W. It allows you to calculate the currency, and then everything else. Checked, gives 36W.

E: Due to the rules of the board I've deleted the exact solution :).

 

[kliker]

thanks irycio I understand it now