A rectangular garden of area 75 ft^2 is bounded on 3 sides by a wall costing $8 per ft, and on the fourth by a fence costing $4 per ft.
What are the most economical dimensions of the garden?

Question

A rectangular garden of area 75 ft^2 is bounded on 3 sides by a wall costing $8 per ft, and on the fourth by a fence costing $4 per ft. 
What are the most economical dimensions of the garden?

jigglypuff314 · Answer

Could someone at least check this for me? pwease?
A = L * W = 75
so  L = 75/W
Cost = 4W + 8(2L + W)
       = 4W + 16L + 8W
       = 12W + 16L
    = 12W + 1200/W
C' = (12(W^2 - 100))/(W^2) = (12(W-10)(W+10))/(W^2)

so W = 10
then  L = 7.5   ?

jigglypuff314 · Answer

@annas can you help? :3

anonymous · Answer

Just a min :)

anonymous · Answer

W = 10 is correct wait lemme check other

anonymous · Answer

oh yes L = 7.5 correct ^_^

anonymous · Answer

sorry I was also doing some other work xD

jigglypuff314 · Answer

(fist pumpt) w00t!
yes! :D Thanks :)