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How Do You Solve These Problems?

1.) A ball is thrown vertically upward from the ground with an initial speed of 80 ft/sec. Its height is given by h = 80t - 16t2. How high does the ball go? When does the ball hit the ground? 3.) A ferry service transporting passengers to an island charges a fare of $10 and carries 300 persons. The manager estimates that the company will lose 15 passengers for each increase in fare of $1. Find the fare that yields the greatest income.

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    Velocity is derivative of position: 80-32t

    Velocity= 0.

    80-32t=0

    32t=80

    t=2.5 sec.

    h=80*2.5-16*(2.5^2)=200-100

    =100 ft.



    when h=0:

    0=80t-16t^2

    -16t^2+80t-0=0

    By quadratic formula:

    t=(-80+/-sqrt(6400+0))/-32

    =(-80+/-80)/-32

    =0/-32, -160/-32

    =0 sec., 5 sec.

    Ball is at h=0 at 0 sec. And again at 5 sec. After being thrown.



    3)

    Let
    "x" be the number of dollars the fare increases.


    Income
    to the company =(10+x)(300-15x)


    -15x^2
    +285x+3000 = 0


    Solve
    it with the help of quadratic formula a=-15 ; b=285 ; c=3000


    Maximum
    income occurs when x=-b/2a = -285/-30 =9.5




    Putting
    X= 9.5 in the equation


    =(10+x)

    =(10+(9.50)= (19.50)



    The
    fare when x=$9.50 is $19.50.


    The
    Income will be max when fare is $19.50
    0 1

    Jannifer 

    answered 2 years ago

    (10+x) (300-15x) = 3000 +150x - 15xx; so x = 5; $15 far yields 15x225 or $3375. $19.50x(300-9.5(15)) = $3071.25
    Report
    Kinggeor

    Kinggeor

    commented 2 years ago

    i mention that you will get the maximum income when the fare is $19.50... so the end result will be $3071.25.. i skipped the last part which you have done in the comment... and still you rated me bad for the whole procedure :( ,,, do you think it's fair??
    Report
    Jannifer

    Jannifer

    commented 2 years ago

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