Answer
Tom has quite an appreciable amount of hair. After 2 days, he gets a trim at the saloon. Then he lets it grow. After 5 days, again he goes to the saloon and gets a better haircut. He continues with his haircut till he gets bald. Again, he lets the hair grow for a day or two, after which he again gets bald.
Work Step by Step
In the first part, the hair grows, till Tom gets a trim after which the hair reduces a bit. Then, again it grows till he cuts his hair again, graph comes to zero, this means he is bald. Again his hair grows, so graph moves up, then again graph comes to zero, that means he gets bald again.