Question

A music stores finds that weekly revenue r(in pesos) earned by the store on the sale of cds is given by the equation r=2 x 2-10x. How many vds must be sold if the revenue form cds is to php 1000 per week?

Answer 1

The number of cds to be sold to hit a weekly revenue of 1000 pesos is 25

Explanation:

Here, we have the revenue function and we want to know the number of cds to be sold to hit a particular revenue value.

Mathematically from the question;

r = 2x^2 - 10x

in the question; r = 1000

so ;

2x^2 - 10x = 1000

divide through by 2

x^2 -5x = 500

so;

x^2 -5x -500 = 0

x^2 -25x + 20x -500 = 0

x (x -25) + 20(x -25) = 0

(x -25)(x + 20) = 0

x -25 = 0 or x + 20 = 0

x = -20 or 25

Since the number of cds cannot be negative, we only select x = 25 as the correct answer