Count on Your Time, your @ssets

Ttime is the most important asset of a student. But this asset does not grow. It only slips out of hand. The wise use of time is very crucial today as there are more candidates to any opportunity than the opportunities itself. The time today most of the students spend on is Facebook. Instead of serving the purpose of networking between people for some or any purpose it has become a network of purposeless activities to kill time and to keep busy for no good reason. The main motive behind such social networking sites my dear friends is not to keep login for whole day and publish your new and indifferent status and feeds, rather it should form a forum for you to serve for a purpose, a means to keep in touch and not keep login. Even the founder of Facebook might not be using his idea too that extent to keep all the day hanging on it. If was it true, he could never have been so capable and developed to develop such a mastermind. The question is not quitting, infact the answer is wisely using.
Talking of time I just recalled another puzzling question about time. Consider this:
Problem :
Mohan lives 24 km from the railway station. He has one hour to catch the train. He leaves home at the speed of  18 km/hr. Travels half the distance and then increases his speed to 30km/hr. He  with this speed for the next quarter of the distance and then plans to speed up again. Now what should be his speed in order to catch the train.
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