tlong di bantu yaaa,ssah bgt

A-B
s = 30 km
t = 1 jam
B-C
s = 50 km
t = 1 jam
C-D
s = 80 km
t = 2 jam

Kelajuan rata-rata dari kota A-D?

Penyelesaian:
Kelajuan rata -rata
= s total / t total
= (30)(50)(80)/(1 + 1 +2)
= 160/4
= 40 m/s