Question

A tube light of 40 W each, 2 fans of 60 W each, and a television of 100 W and an air conditioner of 1 kW are used for 6 hours daily. Find the cost of electrical energy for the
month of August if 1 unit of energy costs Rs. 3.50.​

Answer 1

Given:-

• A tube light of 40 W.

• 2 fans of 60 W each.

• A television of 100 W.

• An air conditioner of 1 kW.

• It were used for 6 hours daily.

• Cost of 1 unit is ₹3.50.

To Find:-

• Cost of electrical energy for the month of August.

Solution:-

Here, We know that,

1 kW = 1000 W

Total energy used in 1 hour = 40 W + 60 W + 60 W + 100 W + 1000 W

                                              = 1260 W

Now, Since it is used 6 hours daily in month of August,

So, Total time energy is used = ( 6 × 31 ) hrs.

                                                 = 186 hrs.

Since, 1 kW = 1000 Watt

So, 1260 watt = $\dfrac{1260}{1000}$ = 1.26 kW

Now, Energy used in 186 hrs.

⇒ 186 × 1.26

⇒ 234.36 kwh

Since, 1 unit = 1 kwh

Now, Cost of electrical energy for the month of August = ₹234.36 × 3.50

                                                            ⇒ ₹820.26

Hence, Cost of electrical energy for the month of August ₹820.26.