PSLE
The students of a test are divided equally into two groups. In the first group, there are 79 less girls than boys. In the second group, there are 45 less boys than girls. 40% of all the students are girls. How many students are there altogether?

	First group		Second group		Total
Comparison 1	50%		50%		100%
Comparison 2	Boys (more)	Girls (less)	Boys (less)	Girls (more)
	1 u + 79	1 u	1 u + 17	1 u + 17 + 45
Comparison 3	Total girls		Total boys
	40%		60%		100%

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

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

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

Total number of boys 
= 1 u + 79 + 1 u + 17
= 2 u + 96

Total number of girls
= 1 u + 1 u + 17 + 45
= 2 u + 62

Number of boys more than girls
= 96 - 62
= 34

20% of the students = 34

1% of the students = 34 ÷ 20 = 1.7

100% of the students
= 100 x 1.7
= 170

Number of students = 170

Answer(s): 170