The total resistance is found by the addition of resistors in parallel, in the equation (1/R_{T})=(1/R_{1})+(1/R_{2})+(1/R_{3}), therefore the total resistance is 1.25ohms. Therefore the current is simply I_{T}=V_{S}/R_{T}, which gives us a current of 14.4A, and using P=IxV, the power dissipated is 259.2W.