Awhite car is traveling at the legal speed limit v0 along an interstate highway. a blue car traveling in the same direction at twice the legal limit draws alongside the white car and (mistakenly) thinks it is a police car. the blue car slows down with constant acceleration a = −ab and the white car continues at its previous constant speed. how far apart are the cars when the blue car’s speed is the legal speed limit?

the distance between two cars becomes when blue car travels at legal speed

Explanation:

Initially the relative speed of the two cars is given as

now the relative acceleration of blue car with respect to white car

now the distance between two cars till the relative speed of two cars comes to zero

so the distance between two cars becomes when blue car travels at legal speed

i don't know that i agree with that but what's the question ?