algebra

The cost of operating an appliance varies jointly as the number of watts, hours of operation, and the cost per kilowatt-hours. It costs $0.45 to operate a 3000-watt air conditioner for 2 hours at a cost of $0.075 per kilowatt-hour. Find the Cost of operating a 122-watt dishwasher for 40 minutes.

How I calculated: TC (total cost)=k (Watts)(cost)(time) .45=k(3000)(.075)(2) K=.001

Cost=K(watts)(time) Cost=(.001)(1200)(.40)
Cost=.48.......is that correct?

  1. 👍
  2. 👎
  3. 👁
  1. less time and lower wattage ... how can the cost be more?

    $0.45 * [(40/60) / 2] * (122 / 3000)

    1. 👍
    2. 👎
  2. dishwasher is actually 1200 watt (not 122 sorry)...but that is what I thought too which is why I am seeking guidance. thank you for your help....what is the formula you used? when fractions are used doesn't that mean its inverse variation? I thought the problem only said joint variation.

    1. 👍
    2. 👎
  3. jointly means multiple variables

    cost to run dishwasher is the cost to run the ac, multiplied by the ratios of the run time and wattage
    ... both time and wattage are direct variation
    ... the ratios are new to old

    new cost =
    ... old cost * (new watts / old watts) * (new time / old time)

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. Business

    Thomas Kratzer is the purchasing manager for the headquarters of a large insurance company chain with a central inventory operation. Thomas’s fastest moving inventory item has a demand of 6000 units per year. The cost of each

  2. Mathematics

    If y varies jointly as the product of x and z,and y=24;when x=3 and z=2.Find y when x=2 and z=5.

  3. variation

    Can you please check my answers? Thanxs! Write an equation that expresses the relationship. Use k as the constant of variation. 20. f varies jointly as b and the square of c. -I got: f=kbc^2 22. r varies jointly as the square of s

  4. calculus

    The operating cost, C, in dollars per hour, for an airplane cruising at a height of h metres and an air speed of 200km/h is given by: C = 4000 + h/15 + 15000000/h for the domain 1000 ≤ h ≤ 20000. Determine the height at which

  1. math

    if Y varies jointly as X and the square of Z, and if Y=24 when X=2 and Z=6, find Y when X=10 and Z=9

  2. Math

    R varies jointly as S and the square of T. If R is 32.4 when S=0.2 and T=9, find R when S=0.5 and T=5. I believe the answer is R=25, could someone check this for me?

  3. trig

    A city averages 14 hours of daylight in June, 10 in December, 12 in both March and September. Assume that the number of hours of daylight varies sinusoidally over a period of one year. Write an expression for n, the number of

  4. HELP!!! Math

    If a varies jointly as b and the square root of c, and a = 21 when b = 5 and c = 36, find a when b = 9 and c = 225.

  1. Algebra

    If f varies jointly as q2 and h, and f=24 when q=2 and h=2, find f when q=3 and h=5

  2. Interediate algebra

    if f varies jointly as q^2 and h, and if f = 72 when q = 3 and h = 4, find h when f = 48 and q = 2

  3. Physics

    A 100 watts light bulb has an average life of 2000 hours. How much energy does it consume over its lifetime? The only thing I got was power=100 watts and time = 2000 hours but I need to convert to seconds and I don't kn how to do

  4. algebra

    z varies jointly with y and the square of x. If x=-2 when y=7 and z=-84,find x when z=-96 and y=2 I just need help figuring out what equation to use.

You can view more similar questions or ask a new question.