Question:
40% of the students in a hall are male. After 10 female students leave, there are equal numbers of male and female students now. Do you know how many male students are in the hall?

Comment:
This is a typical example of challenging word problems at P6. Students can hardly write down a simple expression to solve it. However, I suggest my student using pictures to make the problem much easier, without the use of equations.

The solution by my student: