....................... Product A .................... Product B ...................

Per Piece cost......

6 .................................. 21 ....

Sales ................. \(x - \frac{qx}{100}\) ...................... \(\frac{qx}{100}\) ....................... x

(Assume-Total sales)Total Revenue ........\(r - \frac{tr}{100}\) ..................... \(\frac{tr}{100}\) ......................... r

(Assume - Total revenue)Two equations would be setup:

\(21 * \frac{qx}{100} = \frac{tr}{100}\)

\(\frac{r}{x} = \frac{21q}{t}\) .................... (1)

\(6 * (x - \frac{qx}{100}) = r - \frac{tr}{100}\) ......... (2)

Divide the complete equation (2) by x

\(6 * (1 - \frac{q}{100}) = \frac{r}{x} - \frac{tr}{100x}\)

\(6 * (1 - \frac{q}{100}) = \frac{r}{x} * (1 - \frac{t}{100})\) .................. (3)

Placing value of \(\frac{r}{x}\) (from equation 1) in equation (3)

\(6 * (1 - \frac{q}{100}) = \frac{21q}{t} * (1 - \frac{t}{100})\)

40t = 140q - tq

\(q = \frac{40t}{140-t}\)

Answer = D

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