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Question
Price P for demand D is given as P = 183 +120D - 3D2 Find D for which the price is increasing
Solution
Price function P is given by
`"P" = 183 + 120"D" - 3"D"^2`
Differentiating w.r.t. D
`"dP"/"dD"=120-6D`
If price is increasing then we have `"dP"/"dD">0`
∴ 120 - 6D > 0
∴ 6D < 120
∴ D < 20
∴ The price is increasing for D < 20.
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