Question

a house has 3 tube light, 2 fans, and a television. Each tube light draws 40w. The fan draws 80w. and the television draws 60w on the average all tube light are kept for 5 hrs, 2 fans for 12 hours and television for 5 hours every day. Find the cost of electric energy used in 30 days at the rate of Rs. 3.00 per kwh

Answer 1

Given 3 tube lights, two fans and a television.

1 tube light consumes power = 40 W

There fore ,3 tube lights consume power = 3 x 40 W= 120 W

3 tube lights are kept on for five hours. So, consumption of power by 3 tube lights.

= 5 x 120 W = 600 W-------(1)

1 fan consumes power = 80 W

Therefore, 2 fans consume power = 2 x 80 W= 160 W 2 fans are kept on for 12 hours. So, consumption of power by 2 fans.

= 12 x 160 W = 1920 W-----------(2)

TV draws power = 60 W

TV is kept on for 5 hours = 5 x 60 W = 300 W---------(3)

Therefore, In One day consumption of power = (1) + (2) + (3)

= 600 W + 1920 W + 300 W

= 2820 W = 2.820 KW

Therefore, Total consumption of power in 30 days at Rs. 3 per KW

= 2.820 x 30 x 3 = Rs. 253.80

Answer 2

Given,

3 tube lights,two fans and a television.

Power consumed by 1 tube light = 40W

Power consumed by 3 tube lights =3×40W

=120W

3 tube lights are kept on for five hours.So,consumption of power by 3 tube lights = 5×120W = 600W.........(i)

Power consumed by 1 fan = 80W

power consumed by 2 fans = 2×80W =160W

2 fans are kept on for 12 hours.So,consumption of power by 2 fans = 12x160W = 1920 W........(ii)

Power consumed by television = 60W

TV is kept on for 5 hours = 5×60W =300W .........(iii)

Consumption of power in one day = i+ii+iii

= 60W+1920W+300W

= 2820W

= 2.820 KW

Therefore the total consumption of power in 30 days at RS.3 per kw = 2.820×30×3

= RS.253.80/-