Respuesta :
Answer:
[tex]\mathbf{r = \dfrac{400p }{ 500 -p}}[/tex]
Step-by-step explanation:
Given that:
Last Sunday a certain store sold copies of Newspaper A for $1.00 each
A = 1
and copies of Newspaper B for $1.25 each,
B = 1.25
and the store sold no other newspapers that day. If r percent of the store's revenue from newspaper sales was from Newspaper A and if p percent of the newspapers that the store sold were copies of Newspaper B.
Then ;
[tex]r = \dfrac{A}{A+1.25B} \times 100[/tex] --- (1)
[tex]p = \dfrac{A}{A+B} \times 100[/tex] --- (2)
From (2)
[tex]A+B = \dfrac{A}{p} \times 100[/tex]
[tex]B = \dfrac{A}{p} \times 100-A[/tex]
[tex]B = \dfrac{A( 100-p)}{p}[/tex]
Substituting the value of B into equation (1), we have:
[tex]r = \dfrac{A}{A+1.25 \times { \dfrac{A( 100-p)}{p}}} \times 100[/tex]
[tex]r = \dfrac{A}{A+1.25 \times { A( 100-p)}} \times 100p[/tex]
[tex]r = \dfrac{100p}{p+125 -1.25 p}[/tex]
[tex]r = \dfrac{100p}{125 -0.25 p}[/tex]
multiplying both numerator and denominator by 4; we have
[tex]r = \dfrac{4(100p) }{ 4(125 -0.25) p}[/tex]
[tex]\mathbf{r = \dfrac{400p }{ 500 -p}}[/tex]