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Help with some word problems

  1. Oct 6, 2005 #1
    here is a word problem if someone can post how to set it up and the answer that would be great because i have to do the work any way. I did like 30 problems already and these are the only ones im having a problems with.

    Problem #1 Its in a Linear systems/matrices chapter
    there are 150,000 registered democrats, Republicans, and Indepdents in a country. the number of indep. is 20% of the total number of Demo. and Rep.. In an election, 40% of the Demo. voted, 50% of the Rep., and 70% of the Indep.. The votess totaled 72,000. How many Democrats, Republicans and Independents are registered?

    Problem #2 summarize the given information in matrix form
    AN appliance saleswomen sold 15 washers, 8 dryers, and 13 microwave ovens in March. She sold 12 washers, 11 dryers and 6 microwave ovens in April.

    Problem #3
    The health fare cereal Co. makes three cereals using wheat, oats, and raisins. The proportions of each cereal are.

    cereal wheat oats Raisins

    Lite .75 .25 0
    trim .50 .25 .25
    Health Fare .25 .50 .25

    use matrix Multiplication to determine the number of pounds of wheat, oats, and raisins needed to fill an order of 1480 pounds of Lite, 1840 pounds of Trim and 2050 pounds of health Fare.

    Thanx in advance for the help.
  2. jcsd
  3. Oct 6, 2005 #2


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    Homework Helper

    Re #1, just express what is given in mathematical terms. Example:

    means D + R + I = 150,000. Keep going from there and you'll likely have 3 equations in 3 unknowns.
  4. Oct 6, 2005 #3
    For your first problem:

    I always think that sometimes the question looks so long and wordy that it puts you off. You should think about simplifying the information mathematically first. Assign a letter to each type of voter. Then think about the information you have and try to link it with some simple formulae.

    As a further hint, think about ratios. I don't know how much you know about ratios and their mathematical uses, but they seem to be useful here.

    EDIT: hotvette, you posted just as I was writing out my post :)
  5. Oct 6, 2005 #4
    can you please post the other two equations because im just lost trying to set up the problem. Once have the other two equations i would be able to solve it myself. Thanks for your help
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