Question

15 bulbs of 60 watt works for 6 hour daily and a refrigerator of 360watt works for 5 hours daily .Find the energy required daily if per unit cost Rs.3.

Answer 1

Given,
P1=60watt
=60/1000 KW
=3/50 KW

P2=360watt
=360/1000
=9/25

T1=6hours
T2=5hours


For P1,
Energy(E)=power(P)×Time(T)
E=3/50×6
E=0.36 KWH

For P2,
E2=P2×T2
E2=9/25×5
E2=1.8 KWH

Total energy,
E1+E2=0.36+1.8=2.16 KWH

per unit cost = 3rs
So,
2.16×3=6.48rs

cost will be 6.48 rs