The cost C of printing a magazine is jointly proportional to the number of pages p in the magazine and the number of magazines printed m. (Use k for the constant of proportionality.)

(a) Write an equation that expresses this joint variation.

(b) Find the constant of proportionality if the printing cost is $65,550 for 3800 copies of a 115-page magazine.

(c) How much would the printing cost be for 3500 copies of a 84-page magazine?

Question

The cost C of printing a magazine is jointly proportional to the number of pages p in the magazine and the number of magazines printed m. (Use k for the constant of proportionality.)

(a) Write an equation that expresses this joint variation. 

(b) Find the constant of proportionality if the printing cost is $65,550 for 3800 copies of a 115-page magazine.


(c) How much would the printing cost be for 3500 copies of a 84-page magazine?

aripotta · Answer

a. c = kpm

b. 65550 = k115(3800). 65550 = 437000k. k = 0.15

c. c = 0.15(84)(3500). c = 44100

aripotta · Answer

do you need me to explain that?

anonymous · Answer

No, I understand. Once I saw which formula to use it all made sense. Thank you so much!

aripotta · Answer

no problem :) i literally just learned this lol. so it's still fresh in this little brain o' mine

anonymous · Answer

Thank goodness for that! :)