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Electrical Usage Question

  1. Nov 11, 2013 #1
    A.) A 20-W compact fluorescent lamp replaces a 100-W incandescent bulb. How much energy does it save over its 10,000 hour lifetime?
    B.) At $0.10 per kilowatt-hour, how much money does this save?

    My attempt at answering:

    Difference is wattage is 80-W, multiplied by 10,000 hours is 800,000 (not sure of the label here, is it Kilowatt hours?) saved.

    Is part B just multiplying the 800,000 (UNIT) saved times (0.10) to get $80,000 saved?


    Thank you for your help!
     
  2. jcsd
  3. Nov 12, 2013 #2
    UNIT: simple
    80 watt times 10,000 hours = 80 times 10,000 x watt times hours = 80,000 watt-hours.

    B:
    How many kw-hours is 80, 000 watt-hours?
     
  4. Nov 12, 2013 #3
    80000 watt hours is 80kwh. So multiply 80 kWh to get $8.00?
     
  5. Nov 12, 2013 #4

    adjacent

    User Avatar
    Gold Member

    Ofcourse. 80 x 0.1 = 8

    Or you can do this:
    0.1$ --> 1Kwh
    x --> 80

    Just cross multiply, :wink: .
     
  6. Nov 12, 2013 #5
    80x10000=800,000.
    So you save 80 bucks
     
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