Question 527415
In 1 hour.........90km
In 60 minutes.....90km
In 60/3 minutes..90/3 km
In 20 minutes....30 km

Tranin will go 30km in 20 minutes

Alternatively
Speed = 90km/hour
Time = 20 minutes

Distance = Speed * time
Distance = 90/hour * 20minutes
Distance = 90/60 minutes * 20minutes
Distance = 90/60  * 20
Distance = 30/20 * 20
Distance = 30km