Question

An electric refrigerator rate 400w is used for 8 hours a day. An electric iron box rated 750 w is used for 2 hours a day. Calculate the cost of using the appliance for 30 days if the cost of 1 kwh is Rs.3/-​

Answer 1

Answer:

electric refrigerator

power consumed = 400W

time used in a month = 30×8 = 240hrs

energy consumed by fridge  =  power × time

                                                = 400w × 240hrs

                                                = 400/1000 kw  × 240hrs

                                                 = 96kw

cost of usinf the refrigerator = 96kwh×3

                                                = Rs288

iron box

power = 750w

time used in a month = 30 × 2

                                   = 60hrs

energy consumed by iron box = power × time

                                                   = 750w × 60h

                                                    = 750/1000 kw × 60

                                                    = 45kwh

cost of using the appliance = 45kwh × 3

                                              = Rs135

total amount required = 135 + 288

                                     = Rs423