Question

A 40 watt bulb is used for 2.5 hrs. daily and three bulbs of 60 watts is used for 5 hrs. daily find the
monthly bill (sep) if the cost per unit is 75 paise.

Answer 1

Answer:

22.5 Rs

Explanation:

Energy consumed by 40 watt bulb in 1 day = (40 x 2.5)Wh = 100 Wh = 0.1 kWh

Energy consumed by three 60 watt bulb in 1 day= (3 x 60 x 5) = 900 Wh = 0.9 kWh

September has 30 days so we need to calculate energy consumed of each for 30 days

Energy consumed by 40 watt bulb in 30 days = (30 x 0.1 kWh) = 3 kWh

Energy consumed by three 60 watt bulb in 30 days = (0.9 x 30 kWh) = 27 kWh

Total energy consumed = 27 kWh + 3 kWh = 30 kWh

Cost per unit = 75 paise = 0.75 Rs.

Total cost = 0.75 x 30

                = $\frac{3}{4} X 30 \\ \\= \frac{90}{4}\\\\=22.5 Rs$