Aubrey's school organized a trip to Iran. At first, the ratio of the number of girls to the number of boys who planned to participate in the trip was 7 : 5. On the day of registration, 12 boys decided to withdraw and 12 more girls decided to join in. In the end, the number of boys who participated became 25% of the total children for the trip. How many more girls than boys would visit Iran in the end?

	Girls	Boys	Total
Before	7x1 = 7 u	5x1 = 5 u	12x1 = 12 u
Change	+ 2 u	- 2 u
After	3x3 = 9 u	1x3 = 3 u	4x3 = 12 u

25% = ²⁵₁₀₀ = ¹₄

Since 12 boys withdrew and another 12 girls joined, the total number of children  at first and in the end remains unchanged. Make the total number of children the same. LCM of 12 and 4 is 12.

Number of boys who decided to withdraw
= 5 u - 3 u
= 2 u

2 u = 12

1 u = 12 ÷ 2 = 6

Number of more girls than boys in the end
= 9 u - 3 u
= 6 u
= 6 x 6
= 36

Answer(s): 36