van toc trung binh nguoi di xe dap xuong doc dai 100m la

vtb1=s1/t1=100/25=4 (m/s)

van toc trung binh nguoi di xe dap tren doan duong 50m la

vtb2=s2/t2=50/20=2,5 (m/s)

van toc trung binh tren ca hai quang duong la 

vtb= s1+s2/t1+t1=100+50/25+20=3,3 (m/s)