2010 年

Let $O$ be the origin. If $A$ and $B$ are points lying on the $x$-axis and the $y$-axis respectively such that the equation of the circumcircle of $\triangle OAB$ is $x^2+y^2-16x-12y=0$, then the equation of the straight line passing through $A$ and $B$ is

A circle cuts the $x$-axis at $P$ and $Q$ such that $PQ=6$. If the coordinates of the centre of the circle are $(-5,2)$, find the equation of the circle.

In a school, $55\%$ of the students are boys. It is given that $60\%$ of the boys and $30\%$ of the girls live in Kowloon. Find the probability that a randomly selected student from the school is a girl who lives in Kowloon.

The pie charts below show the expenditures of Albert and Betty in a certain month.

Which of the following must be true?