(a) kWh

(b) Power (kW) x time (h) = Energy (kWh)

(c) 0.014 units

(d) 1.6 units

(e) 71h for Sally; 0.6h (37 minutes) for Lucy

(f)

(i) 40p

(ii) 20p

A2.

(a) £94.32.

(b) £1-56

(c) Cost of sensor would be recouped in two years. In the long term it would be a good idea. Care for the environment/reducing global warming.