eric beans
Junior Member
- Joined
- Sep 17, 2019
- Messages
- 72
The 100W light bulb (cost $.60) is not going to be used anymore and is being replaced with the 20W (cost $3) low energy light bulb.
If electricity is charged at $0.15 per kWh, for how many hours must the low energy bulb be used in order for the lower cost of running it to exactly compensate for its higher initial cost?
A. 0.25
B 250.00
C 200.00
D 160.00
E 720.00
answer: D
why?
What am I misunderstanding here?
.02*.15*t = 3-.6
t= 800
If electricity is charged at $0.15 per kWh, for how many hours must the low energy bulb be used in order for the lower cost of running it to exactly compensate for its higher initial cost?
A. 0.25
B 250.00
C 200.00
D 160.00
E 720.00
answer: D
why?
What am I misunderstanding here?
.02*.15*t = 3-.6
t= 800