Given data:
* The distance to the Grandma house is d = 120 miles.
* The value of the speed limit is v = 60 mph.
* The time for the dinner is t = 5 p.m.
Solution:
The time taken to reach the Grandma house while moving in the speed limit is,
[tex]\begin{gathered} v=\frac{d}{T} \\ T=\frac{d}{v} \end{gathered}[/tex]Substituting the known values,
[tex]\begin{gathered} T=\frac{120}{60} \\ T=2\text{ hours} \end{gathered}[/tex]The time of leaving is,
[tex]\begin{gathered} t_1=t-T \\ t_1=5-2 \\ t_1=3\text{ p.m.} \end{gathered}[/tex]Thus, the time at which the person should leave for grandma's house is 3 p.m.
