Mathematics Instructor of the Ministry of Education visited a leading school in Colombo to check the Mathematics knowledge of the students. He entered the Grade 10 class and told the students, I want you all to answer this question using your mathematics knowledge.

Then he told the class, This morning I traveled to your school by bus. When I got into the bus two other passengers too boarded the bus while five passengers got down. I bought a Rs. 5.00 ticket. At the next halt four passengers boarded the bus while three passengers got down.

On the way at the other bus halts several passengers got in and got off the bus. When I got down from the bus there were ten passengers left in the bus.
Now my question is, How old am I ?

The class teacher and the students were thoroughly confused and were dumb struck !!!.
One student raised his hand and said, Sir you are 48 years old.
The instructor was surprised as he was exactly 48 years old. Then he asked that student as to how he calculated his age.
The student promptly replied, I used my mathematics knowledge and further said that, I have an elder brother at home he is half mad and he is 24 years old.