Car $A$ is traveling at $25 \mathrm{mi} / \mathrm{hr}$ and applies the brakes at the position shown so as to arrive at the intersection $C$ at a complete stop with a constant deceleration. Car $B$ has a speed of $40 \mathrm{mi} / \mathrm{hr}$ at the instant represented and is capable of a maximum deceleration of $18 \mathrm{ft} / \mathrm{sec}^{2} .$ If the driver of $\operatorname{car} B$ is distracted, and does not apply his brakes until 1.30 seconds after car $A$ begins to brake, the result being a collision with car $A$, with what relative speed will car $B$ strike car $A ?$ Treat both cars as particles.