The revenue \(R,\) in dollars, that is generated by selling \(“x”\) units of a certain product is given by

[Vincen]

The revenue \(R,\) in dollars, that is generated by selling \(“x”\) units of a certain product is given by \(9x^2 + bx + c,\) where \(x > 0\) and \(b\) and \(c\) are constants. Find the value of \(b.\)

(1) The revenue generated by selling \(200\) units of the product is \(54,0000.\)
(2) The roots of the equation \(ax^2 - bx + c\) are \(20\) and \(9.\)

Answer: C

Source: e-GMAT