there are 12 inches in 1 foot, so in 25 feet there are then 25(12) inches, or 300 inches.
now, we know that 300 inches then, is 6 bucks, how much is it for 1 only?
[tex]\bf \begin{array}{ccll}
inches&\$\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
300&6\\
1&x
\end{array}\implies \cfrac{300}{1}=\cfrac{6}{x}\implies x=\cfrac{1\cdot 6}{300}\impliedby 2~pennies[/tex]