A theatre is comparing two lighting systems for a rehearsal.
| lighting system | total power | time switched on |
|---|---|---|
| R | 1.8 kW | 45 minutes45\ \mathrm{minutes}45 minutes |
| S | 1.2 kW | 80 minutes80\ \mathrm{minutes}80 minutes |
Calculate which lighting system transfers less energy during the rehearsal and the difference in energy transferred by the two systems.