The following text is for questions 16 to 20.

    The holidays had come. At first, I didn't know how to spend my long holiday. I didn't have any plans because my parents were very busy. My father was finishing his project, while my mother was taking care of my little sister. She was just five months old.

    Fortunately, one of my friends, Zaky, didn't have any plans either. So we spent the holiday together. During the holiday, he came to my house almost every day.

    We did a lot of things. On the first day, we rode a bicycle and went around the city. We stopped at some shops and enjoyed window-shopping. The second day, I taught Zaky how to play basketball. We spent three
days just to get him able to shoot well. In the last two days, we visited museums in our city; they were Ronggowarsito and Mandala Bakti. We learned a lot from the collections in the museums.

20. How many days did Zaky practise to serve well?