Question

Three identical resistors are connected in series. When a certain potential difference is applied across the combination, the total power dissipated is 18.0 W. What power would be dissipated if the three resistors were connected in parallel across the same potential difference?

Identical? If in parallel, instead of the resistance 3R in series, the resistance will be R/3. So total current will be nine times as much, at the same voltage.

What does that tell you about power?

Identical? If in parallel, instead of the resistance 3R in series, the resistance will be R/3. So total current will be nine times as much, at the same voltage.

What does that tell you about power?

If the potential remains the same, then according to the equation I = PV, the power would also be nine times as much. Thanks so much for your help!