You know that the boat traveled 10 miles on 1/3 hours.
To determine how much time it will take the sailboat to travel 120miles at the same speed, you can use cross multiplication:
10miles_____1/3hr
120miles_____x hr
Both relationships are at the same ratio, so that:
[tex]\begin{gathered} \frac{\frac{1}{3}}{10}=\frac{x}{120} \\ \frac{1}{3}\cdot\frac{1}{10}=\frac{x}{120} \\ \frac{1}{30}=\frac{x}{120} \end{gathered}[/tex]-Multiply both sides by 120:
[tex]\begin{gathered} 120\cdot\frac{1}{30}=120\cdot\frac{x}{120} \\ 4=x \end{gathered}[/tex]The boat will take 4 hours to travel 120miles
