Answer
The velocity of the Jeep relative to an observer in the Ford is $130~km/h$ north
Work Step by Step
Let north be the positive direction.
Let $v_{J,r}$ be the velocity of the Jeep relative to the road.
$v_{J,r} = 82~km/h$
Let $v_{F,r}$ be the velocity of the Ford relative to the road.
$v_{F,r} = -48~km/h$
We can find $v_{J,F}$, the velocity of the Jeep relative to the Ford:
$v_{J,r} = v_{J,F}+v_{F,r}$
$v_{J,F} = v_{J,r}-v_{F,r}$
$v_{J,F} = 82~km/h-(-48~km/h)$
$v_{J,F} = 130~km/h$
The velocity of the Jeep relative to an observer in the Ford is $130~km/h$ north
