How Long Will It Take?

A martial arts student went to his Sensei and stated, "I am devoted to studying your martial art. How long will it take me to master it." The Sensei's reply was casual, "Ten years." Impatiently, the student answered, "But I want to master it faster than that. I will work very hard. I will practice everyday, ten or more hours a day if I have to. How long will it take then?" The Sensei thought for a moment, "20years."