Thread: division of decimals

A standard 75-watt lightbulb costs $0.75 nad lasts about 800 hr. An energy efficient flourescent bulb that gives off th esame amount of light costs $5.00 and lasts about 10,000 hr.

1.) how many standard lightbulbs would needed to provide 10,000 hr of light?


2.) How much would it cost using standard lightbulbs to provide 10,000 hr. of light?


3.) which one is more cost effective long term?



Any help on how to solve these?

Originally Posted by benjixbunn

A standard 75-watt lightbulb costs $0.75 nad lasts about 800 hr. An energy efficient flourescent bulb that gives off th esame amount of light costs $5.00 and lasts about 10,000 hr.

1.) how many standard lightbulbs would needed to provide 10,000 hr of light?

10000/800 = ? , round to the nearest whole number since you cannot buy a fraction of a bulb


2.) How much would it cost using standard lightbulbs to provide 10,000 hr. of light?

(solution to #1) times (cost of a standard bulb)


3.) which one is more cost effective long term?

what do you think?

...

Major savings would be in reduced cost of electricity. The cost efficient light would require 25% energy of the regular bulb


bjh