Always remember this relationship: Speed = Distance/ Time.

For Hubert: Speed = 10kph, time = 10 mins, Distance = unknown.

For Banjo: Speed = 8kph, time = 10 mins, Distance = unknown.

Lets D1 = distance traveled by Hubert in 10mins

D2 =distance traveled by Banjo in 10mins

Then solve for individual distances traveled using the relationship above:

For Hubert: D1 = Speed x Time

D1 = (10km/hr)(10min)(1hr/60min)

D1 = 100/60 km

D1 = 1.67 km

For Banjo: D2 = Speed x Time

D2 = (8km/hr)(10min)(1hr/60min)

D2 = 80/60 km

D2 = 1.33 km

Since they traveled in opposite direction after 10 mins, just add their individual distances//then Dtotal = 1.67 + 1.33 = 3 km..