Let they have traveled x miles withbb50 mph and y miles with 10 mph
S0
[tex]x+y=260[/tex]Now the total time of travel is 6 hours
So
[tex]\begin{gathered} \frac{x}{50}+\frac{y}{10}=6 \\ \frac{x+5y}{50}=6 \\ x+5y=300 \\ (260-y)+5y=300 \\ 4y=300-260 \\ 4y=40 \\ y=10 \end{gathered}[/tex]So they drive 10 miles at 10mph