A plane travels 350 km south along a straight path with an average velocity of 125 km/h to the south. The plane has a 30 minute layover, and then travels 220 km south with an average velocity of 115 km/h to the south. What is the average velocity for the trip?

Question

jack1 · Answer

v = distance / time

so leg 1 of journey:
V1 = Dist 1 / time 1
125 = 350 / time 1
2.8 hrs = time 1

leg 2: layover: time 2 = 30 mins = 0.5 hrs

leg 3 :
Veloc 3 = Dist 3 / Time 3
115 = 220 / time 3
time 3 = 1.91 hours

jack1 · Answer

therefore: 
average velocity for whole trip = distance traveled for whole trip / time taken for whole trip
V av = (D1 + D2 + D3) / (T1 + T2 + T3)
V av = (350 + 0 + 220) / (2.8 + 0.5 + 1.9)
V av = 570 km / 5.21 hrs
V av = ?

jack1 · Answer

can you work it out from here?