MATH

posted by .

Furnace repairs

A repairman purchased several furnace -blower motors for a total cost of $210. If is cost per motor had been $5 less, he could have purchased one additional motor. How many motors did he buy at the regular rate?

Please help

  • MATH -

    regular rate = r
    discount rate = (r-5)
    number bought = n
    number that would have been bought = (n+1)
    so
    210 = r n
    and
    210 = (r-5)(n+1) = r n + r - 5 n -5
    from the first equation r = 210/n
    then the second
    215 = (210/n)n +210/n -5 n
    5 = 210/n -5 n
    5 n = 210 -5 n^2
    n^2 + n - 42 = 0
    (n-8)(n+7)=0
    n = 8

  • sorry factored wrong -

    sorry
    (n+7)(n-6) = 0
    n = 6

  • MATH -

    check
    r = 210/n = 35
    r-5 = 30
    n+1 = 7
    30 * 7 = 210 check

  • MATH -

    thank you very much

  • MATH -

    HELP!!!!!I need a better explination.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. electrical trade theory

    what r the 2 main characteristics of a shunt connected motor?
  2. A. Production

    A toy manufacturing makes its own wind-up motors, which are then put into its toys. While the toy manufacturing process is continous, the motors are intermittent flow. Data on the manufacture of the motors appears below. Annual demand …
  3. Math

    Kee had to buy 2 tires and patch the tires on his bicycle 3 times this year. How much did he spend repairing his bicycle if these were all the repairs he needed?
  4. algbra

    If fuses cost $2.35 each, and each motor requires 3 fuses, how many motors can be supplied with $493.50 worth of fuses?
  5. FINANCIAL ACCOUNTING

    a) Discuss General Motors in the context of the forces considered in performing an environmental scan. b) Discuss the risks that General Motors needs to consider in conducting its operations c) Explain whether you believe that GM can …
  6. pstat.................HELP........................

    Electric motors coming off two assembly lines are pooled for storage in a common stockroom, and the room contains an equal number of motors from each line. Motors are periodically sampled from that room and tested. It is known that …
  7. algebra

    A bookstore can purchase several calculators for a total cost of $350. If each calculator cost $2 less, the bookstore could purchase 20 additional calculators at the same total cost. How many calculators can be purchased at the regular …
  8. algebra

    A repairman purchased several furnace-blower motors for a total cost of $150. If his cost per motor had been $5 less, he could have purchased 1 additional motor. How many motors did he buy at the regular rate?
  9. math

    A repairman purchased several furnace-blower motors for a total cost of $150. If his cost per motor had been $5 less, he could have purchased 1 additional motor. How many motors did he buy at the regular rate?
  10. AP Physics

    An electric furnace runs nine hours a day to heat a house in January (31 days). The heating element has a resistance of 10.6 ohms and is hooked up to a 240 Volt potential. What does it cost to run the furnace in the month of January …

More Similar Questions