Question

suppose in a house there are two bulbs of 40w each , two fans of 100w each. All of them are used for two hours a day . Find the cost of electric energy used in 30 days at RS:3 per unit.​

Answer 1

Given :-

• Two bulbs of 40w and Two fans of 100w consumes energy.

• The cost for 1 unit = Rs 3

Solution :-

Here,

The energy consumed by two bulbs

Energy = Power * Time

= 2 * 40 * 2

= 0.16 kwh

The energy consumed by two fans

= Power * Time

= 2 * 100w * 2 = 0.4kwh

Now,

The total energy consumed by two fans and two bulbs .

= 0.16 + 0.4 = 0.56 kwh

The energy consumed in 30 days

= 30 * 0.56 = 16.8 kwh

The cost of 1 unit = Rs 3

The cost of 16.8 kwh = 16.8 * 3

= Rs 50.4

Hence, The cost of electric energy used is Rs 50.4 $.$

Answer 2

40*2+100*2=280

in kw=2.80kw

time =2hours

energy=power*time

=2.80*2

=5.6units in one day

in 30 days = 5.6*30=168units

cost=168*3=504rupees