Answer:
A) -50
Step-by-step explanation:
The given proportion relation is
[tex] \frac{r + 10}{4} = \frac{r}{5} [/tex]
The least common denominator is 20
We multiply through by 20 to get
[tex]20 \times ( \frac{r + 10}{4}) = \frac{r}{5} \times 20 [/tex]
We simplify to get;
[tex]5(r + 10) = 4r[/tex]
Expand the parenthesis to get:
[tex]5r + 50 = 4r[/tex]
[tex]5r - 4r = - 50[/tex]
This simplifies to
[tex]r = - 50[/tex]
