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and to have a life of 600 hours at 3 watts per candle. The current is assumed to cost 10 cents per h.p. hour.
Lamps 85 cts. each—Life 600 hrs. at 3 Watts per Candle.
Current costs 10 cts. per ㏋. per hour.
The cost of the current is determined from the following formula:
Current cost=
w.p.c. × 16 × 100 × 1000 × cost of ct. per h. p. per hour
746
