In an examination, 35% of total students failed in Hindi, 45% failed in English and 20% failed in both. Find the percentage of those studnets who passed in both the subjects ?
4 hrs after a goods train passed a station, another train travelling at a speed of 72 km/hr following that goods train passed through that station. If after passing the station the train overtakes the goods train in 8 hours. What is the speed of the goods train?