13 cups of water -- 2 cups of concentrated cleaner (the ratio is [tex]\dfrac{13}{2}[/tex])
w cups of water -- 5 cups of concentrated cleaner (the ratio is [tex]\dfrac{w}{5}[/tex])
Write a proporion:
[tex]\dfrac{13}{2}=\dfrac{w}{5}.[/tex]
Answer: option A