First order RL RC question
Start working. Do not expect numerous ready to use solutions because they will very likely collect downvotes.

The capacitor has had time to get charged since minus eternity. You should be able to calculate how much there's voltage at t=0.

The capacitor is discharged to a resistor network which can reduced to one resistor when seen from capacitor's perspective. Find the discharging law from certain initial capacitor voltage when there's only one resistor load.

Calculate from discharging law by using voltage division rules Vo and Io as functions of time.

The question wants "total dissipated power" in the rightmost resistor. That can be presented as a function of time. I guess your teacher expects total dissipated energy, so you must integrate the power from t=0 to plus eternity or deduce the energy from the available energy and dissipation power distribution in the network.