Sprint events in track and field usually consists of the 100 m , 200 m and 400 m race though 60 m dashers are also held on occasion . These races are largely based upon the athlete's ability to accelerate to his or her maximum speed in the quickest time possible . Girish wants to participate in 200 m Sprint . He can currently run that distance in 45 sec . But he wants to do that in under 30 sec . With each day of practice , it takes him 2 sec less.Respond to the above situation by answering following questions .
1. What is minimum number of days he need to practice till his goal is accomplished?