In an announcement on a railway station, a passanger hears that the last train has passed the station t1=30min earlier than his train. On next station, another announcement reveals him that the first train arrives t2=20 min earlier than his train. The distance between stations is S=20km. Reading time from his watch the passanger calculates average speed of his train to be Vp=60km/h relying on the announcement and the passanger calculations, determine th average speed V of first train.

In an announcement on a railway station, a passanger hears that the la

1.	In an announcement on a railway station, a passanger hears that the last train has passed the station t1=30min earlier than his train. On next station, another announcement reveals him that the first train arrives t2=20 min earlier than his train. The distance between stations is S=20km. Reading time from his watch the passanger calculates average speed of his train to be Vp=60km/h relying on the announcement and the passanger calculations, determine th average speed V of first train.
Answer» In an announcement on a railway station, a passanger hears that the last train has passed the station t1=30min earlier than his train. On next station, another announcement reveals him that the first train arrives t2=20 min earlier than his train. The distance between stations is S=20km. Reading time from his watch the passanger calculates average speed of his train to be Vp=60km/h relying on the announcement and the passanger calculations, determine th average speed V of first train.