A boat on the ocean is $4mi$ from the nearest point on a straight shoreline; that point is $12mi$ from a restaurant on the shore. A woman plans to row the boat straight to a point on the shore and then walk along the shore to the restaurant. Complete parts $($a$)$ and $($b$)$ below.

a$.$ If she walks at $3m\frac{i}{h}r$ and rows at $2m\frac{i}{h}r,$ at which point on the shore should she land to minimize the total travel time?

To minimize the total travel time, the boat should land miles from the restaurant.

$($Type an exact answer, using radicals as needed.$)$