....................... 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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Quick way to do this one..

Let the total number of products sold be 100..

We will work with ratio of the individual revenues for Product A and Product B

\(\frac{21Q}{6(100-Q)} = \frac{T}{100-T}\)

Answer (D)
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