# What will be the Monthly Bill? If

In a house, there are eight 40 watt bulbs which are burning for 5 hrs a day and four 80 watt bulbs burning for 10 hrs a day. If electricity costs ₹ 2 per kilowatt per hour, what is the monthly bill?

- ₹ 328
- ₹ 216
- ₹ 268
- ₹ 288

**Answer: (4) Rs.288**

**Explanation:-**

Eight bulbs are of 40 watt.

Consumed electricity by eight bulbs of 40 watt in 5 hrs. = 8 x 40 x 5 = 1600 watts.

Consumed electricity by four bulbs of 80 watt in 10 hrs. = 4 x 80 x 10 = 3200 watts.

Total consumed electricity in a day = 1600 + 3200 = 4800 watts.

Consumed electricity in a month = 4800 x 30 = 144000 watts

1 watt = 1/1000 kw

Then, 144000 w = 144000/1000 kw

= 144 kw

The cost of 1 kw electricity = Rs.2 per hour.

Therefore, the cost of 144 kw electricity = 144 x 2 = Rs.288

Hence, Rs.288 is the monthly bill of that house.