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Posers and Puzzles

Posers and Puzzles

  1. Subscriber joe shmo On Vacation
    Strange Egg
    19 Nov '07 03:17 / 1 edit
    I have a question this is what I have come up with, here is the problem

    an organization determines that the cost per person of chartering a bus is given by the formula

    C(x) = (100 + 5x)/x

    where x is the number of people in the group and C(x) is a dollar amount

    Its asking me to find C-1(x) and explain what it represents, to clear up my notation its asking for the inverse of C(x)

    The problem is when I go to fing C-1(x) I come up with

    C-1(x) = ( xy - 100)/5

    I arrived at this by using the method i was taught replacing C(x) with y and replacing the x's in the original C(x) function with y's to get:

    x = (100 + 5y)/y then I am supposed to rearrange for y. this is apparently where i run into problems.

    can anyone point out where Im screwing up.

    Thank you
  2. Subscriber joe shmo On Vacation
    Strange Egg
    19 Nov '07 03:50 / 1 edit
    Originally posted by joe shmo
    I have a question this is what I have come up with, here is the problem

    an organization determines that the cost per person of chartering a bus is given by the formula

    C(x) = (100 + 5x)/x

    where x is the number of people in the group and C(x) is a dollar amount

    Its asking me to find C-1(x) and explain what it represents, to clear up my notation i parently where i run into problems.

    can anyone point out where Im screwing up.

    Thank you
    i think I found my error

    if I break C(x) = (100 + 5x)/x into C(x)= 100/x + 5x/x

    I get C-1(x) = 100/x-5

    and composing the functions I get C(C-1(x)) = x which is proof that they are inverse. However, Im still having trouble figuring out what C-1(x) means as far as the charterbus situation
  3. Subscriber joe shmo On Vacation
    Strange Egg
    19 Nov '07 04:04
    Originally posted by joe shmo
    i think I found my error

    if I break C(x) = (100 + 5x)/x into C(x)= 100/x + 5x/x

    I get C-1(x) = 100/x-5

    and composing the functions I get C(C-1(x)) = x which is proof that they are inverse. However, Im still having trouble figuring out what C-1(x) means as far as the charterbus situation
    i see there is a domain restriction in C-1(x)Domain: x > 5
    because there would be no people chartering the bus i suppose otherwise......could this be it?
  4. Subscriber joe shmo On Vacation
    Strange Egg
    19 Nov '07 04:08
    Originally posted by joe shmo
    I have a question this is what I have come up with, here is the problem

    an organization determines that the cost per person of chartering a bus is given by the formula

    C(x) = (100 + 5x)/x

    where x is the number of people in the group and C(x) is a dollar amount

    Its asking me to find C-1(x) and explain what it represents, to clear up my notation i ...[text shortened]... parently where i run into problems.

    can anyone point out where Im screwing up.

    Thank you
  5. Subscriber AThousandYoung
    It's about respect
    19 Nov '07 06:12
    Originally posted by joe shmo
    I have a question this is what I have come up with, here is the problem

    an organization determines that the cost per person of chartering a bus is given by the formula

    C(x) = (100 + 5x)/x

    where x is the number of people in the group and C(x) is a dollar amount

    Its asking me to find C-1(x) and explain what it represents, to clear up my notation i ...[text shortened]... parently where i run into problems.

    can anyone point out where Im screwing up.

    Thank you
    y = (100+5x)/x

    xy = 100+5x

    xy - 5x = 100

    x(y-5) = 100

    x = 100/(y-5)
  6. 19 Nov '07 10:09
    Originally posted by joe shmo
    However, Im still having trouble figuring out what C-1(x) means as far as the charterbus situation
    What it means: the inverse function will give you the number of people in the group given the cost.