# With what average speed did the body move, if the part of the path is equal to 108 km

**With what average speed did the body move, if the part of the path is equal to 108 km, it passed in 36 km / h. a part equal to 108 km at a speed of 54 km / h, and a part equal to 72 km for 72 km / h?**

V1 = 36 km / h.

S1 = 108 km.

V2 = 54 km / h.

S2 = 108 km.

V3 = 72 km / h.

S3 = 72 km.

Vav -?

To find the average speed of movement Vav, it is necessary to divide the entire path traveled by the train S by the time of its movement t along the entire path: Vav = S / t.

The travel time of the entire path is expressed by the sum: t = t1 + t2 + t3, where t1, t2, t3 are the travel time on the first, second and third part of the path.

t1 = S1 / V1.

t1 = 108 km / 36 km / h = 3 h.

t2 = S2 / V2.

t2 = 108 km / 54 km / h = 2 h.

t3 = S3 / V3.

t3 = 72 km / 72 km / h = 1 h.

t = 3 h + 2 h + 1 h = 6 h.

S = S1 + S2 + S3.

S = 108 km + 108 km + 72 km = 288 km.

Vav = 288 km / 6 h = 48 km / h.

Answer: the average body speed was Vav = 48 km / h.