Buses leave Kolkata to Durgapur every hour on hour. Separate buses leave

Buses leave Kolkata to Durgapur every hour on hour. Separate buses leave Durgapur to Kolkata every hour on half hour. It takes 5 hours between Kolkata and Durgapur. How many Kolkata bound buses will a bus from Kolkata to Durgapur
pass by on the same road?​