jogs
north for exactly 5.0 min at an average speed of 8.0 km/h.
Convert velocity from km/h to km/min
V = 8.0 km/h 1h/60min = 2/15 km/min
Distance = Vt = [2/15 km/min]5min = 2/3 km
He continues
north at a speed of 12.0 km/h for the next 30.0 min.
Again convert km/h to km/min
V = 12.0 km/h 1h/60min = 1/5 km/min
D = Vt = [1/5 km/min]30min = 6 km
He then turns
around and jogs south at a speed of 15.0 km/h for 15.0 min.
Position before turning around
X = 2/3 km + 6 km = 20/3 km North
D = Vt = 15.0 km/h (1/4 h) = 15/4 km
New position: 20/3 km North - 15/4 km South = 35/12 km North
Then he jogs
south for another 20.0 min at 8.0 km/h.
D = Vt = 8.0km/h [1/3 h] = 8/3 km
New position 35/12 km North - 8/3 km South = 3/12 = 1/4 km North
Total distance jooged = 20/3 km + 15/4 + 8/3 km = 157/12 km = 13.08 km ≈ 13.1 km
He walks the rest of the way
home
He will have to walk 1/4 km = 0.25 km to get home after he finishes jogging
