Math Is Fun Forum

taylor_2009

Member

Registered: 2010-01-25

Posts: 28

Calculus word problem? Please help.

(a)Let A(x) denote the number (in hundreds) of computers sold when x thousand dollars is spent on advertising. Represent the following statement by equations involving A or A': When four thousand dollars were spent on advertising the number of computers sold was 1100 and it was rising at the rate of 80 computers for each 1000 dollars spent on advertising.

(b)Estimate the number of computers that will be sold if $6000 is spent on advertising.

For part a I got: A(4)=11 and A'(4)=0.8

I don't know how to do part b. Any help would be appreciated.

John E. Franklin

Member

Registered: 2005-08-29

Posts: 3,588

Re: Calculus word problem? Please help.

(ComputerHundredsSold - 11) = 0.8(AdvertisingThousands - 4)

b.) AdvertisingThousands = 6

ComputersHundredsSold - 11 = 0.8 ( 6 - 4 )

ComputersHundredsSold = 1.6 + 11

ComputersHundredsSold = 12.6

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igloo myrtilles fourmis

taylor_2009

Member

Registered: 2010-01-25

Posts: 28

Re: Calculus word problem? Please help.

Thank you! That was right.