The car, approaching the traffic light, brakes and, having covered the distance of 45m in 5s

The car, approaching the traffic light, brakes and, having covered the distance of 45m in 5s, stops and immediately starts moving and in 15 seconds it covers 75m, calculate the average speed of the car along the entire path

S1 = 45 m.
t1 = 5 s.
S2 = 75 m.
t2 = 15 s.
Vav -?
To find the average speed Vav, it is necessary to divide the entire distance S that the car has traveled by the time of its movement t: Vav = S / t.
S = S1 + S2.
t = t1 + t2.
Vav = (S1 + S2) / (t1 + t2).
Vav = (45 m + 75 m) / (5 s + 15 s) = 6 m / s.
Answer: the average speed of the vehicle was Vav = 6 m / s.