31.. An electric refrigerator rated 400 W is used for 8 hours a day. A

1.	31.. An electric refrigerator rated 400 W is used for 8 hours a day. An electric ironbox rated 750 W is used for 2 hours a day. Calculate the cost of using theseappliances for 30 days, if the cost of 1 kWh is Rs. 3/-.
Answer» 1) - refrigerator power = 400w time. = 8 hrs electrical energy = power* time E. E. = 400/10008 = 3.2kwh (2) - iron box power = 750w time. = 2hrs electrical energy = 750/10002 = 1.5kwh cost of 1kwh = rupees 3 cost of 1.5kwh = 4.5 rs cost of month = 4.5*30 = 135 rs hope it HELP you please & mark it as brainliest

31.. An electric refrigerator rated 400 W is used for 8 hours a day. An electric ironbox rated 750 W is used for 2 hours a day. Calculate the cost of using theseappliances for 30 days, if the cost of 1 kWh is Rs. 3/-.

Answer»

1) - refrigerator

power = 400w

time. = 8 hrs

electrical energy = power* time

E. E. = 400/1000*8

= 3.2kwh

(2) - iron box

power = 750w

time. = 2hrs

electrical energy = 750/1000*2

= 1.5kwh

cost of 1kwh = rupees 3

cost of 1.5kwh = 4.5 rs

cost of month = 4.5*30

= 135 rs

hope it HELP you please & mark it as brainliest