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Number of new cars purchased in a city can be modeled by the equation

  1. Jun 3, 2003 #1
    Help ASAP plz!!!

    Can someone plz show me how to do the 2 problems below? I really don't know how...Thanks
    1)The number of new cars purchased in a city can be modeled by the equation C=22t^2+17tt+9933, where C is the number of new cars and t=0 corresponds to the number of new cars purchased in 1976. In what year will the number of new cars reach 38,000?

    2)During the years 1992-1996, the average number of green grapes, G, sold by a large farmer's market can be modeled by
    G= -11t^2+2.02t+41.09. The average number of red grapes, R, sold by the farmer's market can be modeled by R= .004t^2-.688t+79.06. Determine the model representing the number of grapes, N, sold from 1992-1996.
     
  2. jcsd
  3. Jun 3, 2003 #2
    Here are some hints for you.

    We know C corresponds to the number of new cars purchased. You are given an equation showing the relation between C, number of cars purchased and t, where t=0 in 1976.
    Can you use 38 000, which is the number of new cars sold in a particular year, to find out t? (Hint: you need to solve a quadratic equation)
    After t is found, how can you relate t to the year 38000 cars are sold? (Hint, t=0 represents year 1976, how about t=1, t=2 and so on?)

    You can use the way question 1 was asked as a reference.
    Take t=1 represent year 1992.

    In 1992, the average number of green grapes sold:
    G1992= -11t^2+2.02t+41.09
    the average number of red grapes sold:
    R1992= .004t^2-.688t+79.06
    total number of grapes sold in 1992 = G1992+R1992

    In 1993, the average number of green grapes sold,
    G1993 = -11(t+1)^2+2.02(t+1)+41.09
    The average number of red grapes sold:
    R1993= .004(t+1)^2-.688(t+1)+79.06.
    Total number of grapes sold in 1993 = R1993+G1993

    Can you continue from here?
     
  4. Jun 3, 2003 #3

    Hurkyl

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    And we have a homework help forum specifically for, well, homework help.
     
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