Question

The following table gives the electrical appliances used, their power and the average time for which they are used each day in a home. Estimate the monthly electricity bill if the rate is 60 paise per unit.

Sr.no.	Name	Nos.	Power rating	Time/day
1	Bulb	4	100 W	7.5 hr
2	Fans	2	50 W	10 hr
3	T.V.	1	100 W	2 hr
4	Iron	1	500 W	1 hr
5	Electric stove	1	750 W	2 hr

Answer 1

We first calculate the total kWh consumption of each appliance per day. This is done is below:

(1) Bulbs: kWh consumption =`(4 xx 100)/1000  "kW" xx 7.5 "h" = 3  "kWh"`

(2) Fans: kWh consumption = `2 xx 50/1000  "kW" xx 10  "h" = 1 "kWh"`

(3) T.V. kWh consumption = `1 xx 100/1000  "kW" xx 2  "h" = 0.2  "kWh"`

(4) Iron: kWh consumption = `1 xx 500/1000  "kW" xx "1 h" = "0.5 kWh"`

(5) Electric stove: kWh consumption = `1 xx 750/1000 "kW" xx "2 h" = "1.5 kWh"`

∴ Total kWh consumption per day = (3 + 1 + 0.2 + 0.5 + 1.5) kWh

= 6.2 kWh = 6.2 unit

∴ No. of.units consumed in one month = 6.2 × 30 unit = 186 units

∴ Monthly electricity bill = 186 × 60 paise = Rs. 111.60.