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Question
The money to be spent for the welfare of the employees of a firm is proportional to the rate of change of its total revenue (Marginal revenue). If the total revenue (in rupees) recieved from the sale of x units of a product is given by R(x) = 3x2 + 36x + 5, find the marginal revenue, when x = 5, and write which value does the question indicate ?
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Solution
Since, marginal revenue is the rate of change of total revenue with respect to the number of units sold, we have
\[\text { Marginal revenue } (\text { MR }) = \frac{dR}{dx} = 6x + 36\]
\[\text { When x } = 5,\text { MR } = 6\left( 5 \right) + 36 = 66\]
Hence, the required marginal revenue is ₹66.
It indicates the extra money spent when number of employees increased from 5 to 6.
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