Harris's school organized a trip to Malta. At first, the ratio of the number of boys to the number of girls who planned to participate in the trip was 7 : 4. On the day of registration, 35 girls decided to withdraw and 35 more boys decided to join in. In the end, the number of girls who participated became 25% of the total children for the trip. How many children would visit Malta in the end?

	Boys	Girls	Total
Before	7x4 = 28 u	4x4 = 16 u	11x4 = 44 u
Change	+ 5 u	- 5 u
After	3x11 = 33 u	1x11 = 11 u	4x11 = 44 u

25% = ²⁵₁₀₀ = ¹₄

Since 35 girls withdrew and another 35 boys joined, the total number of children at first and in the end remains unchanged. Make the total number of children the same. LCM of 11 and 4 is 44.

Number of girls who decided to withdraw
= 16 u - 11 u
= 5 u

5 u = 35

1 u = 35 ÷ 5 = 7

Number of children that would visit Malta in the end
= 33 u + 11 u
= 44 u
= 44 x 7
= 308

Answer(s): 308