PSLE
The students of a test are divided equally into two groups. In the first group, there are 47 less boys than girls. In the second group, there are 9 more boys than girls. 40% of all the students are boys. How many students are boys?

	First group		Second group		Total
Comparison 1	50%		50%		100%
Comparison 2	Girls (more)	Boys (less)	Girls (less)	Boys (more)
	1 u + 47	1 u	1 u + 19	1 u + 19 + 9
Comparison 3	Total boys		Total girls
	40%		60%		100%

Number of students in the first group and the second group is equal.

Percentage of students who are girls
= 100% - 40%
= 60%

Percentage of more girls than boys
= 60% - 40%
= 20%

Total number of girls 
= 1 u + 47 + 1 u + 19
= 2 u + 66

Total number of boys
= 1 u + 1 u + 19 + 9
= 2 u + 28

Number of girls more than boys
= 66 - 28
= 38

20% of the students = 38

1% of the students = 38 ÷ 20 = 1.9

40% of the students
= 40 x 1.9
= 76

Number of students that are boys = 76

Answer(s): 76