Two cars leave towns 680 kilometers apart at the same time and travel toward each other. one cars rate is 14 kilometers per hour more then the others. if they meet in 4 hours what is the rate of the faster car?

Speed of the faster car . . .  S            kph
Speed of the slower car . . .  S - 14    kph

Sum of the speeds of the cars = (S) + (S - 14)  =  2S - 14    kph

The cars are driving toward each other, so the space between them
is shrinking at the rate of  (2S - 14) kph.

                         Distance  =  (speed)  x  (time)

                           680 km  =  (2S-14  kph) x (4 hrs)

                                        =     8S - 56     km
Add 56
to each side:         736 km  =    8S          km

Divide each
side by  8 hrs:          S  =  92  kph 

Whose mistake? can you give more details to what the question is asking?