Two cars leave the same intersection at hours

MATHEMATICS · Single correct · AP · Calculus AB · Contextual Applications of Differentiation · Contextual Applications of Differentiation

Problem

Two cars leave the same intersection at

t=0

hours. Car P travels east with a velocity (in mph) given by

v_P(t)=30-4t

, while Car Q travels north at a constant 10 mph. At what time, in hours, does the distance between the cars stop increasing? (a)

12.5\text{ h}

(b)

10\text{ h}

(c)

5\text{ h}

(d)

7.5\text{ h}