Contest April 2012

The April contest has ended.

The Easter Bunny rides his bicycle along the railroad from Ostermundigen to Hasliberg. Every 30 minutes a train comes towards him from the opposite direction. Every 45 minutes a train passes him from behind. But actually the trains go at the same frequency in both directions. 

What is the real time difference in minutes between two trains?

From those who sent us correct solutions by April 30th, we will draw two winners and send them a voucher for our test.