Salik's school organized a trip to Brazil. At first, the ratio of the number of girls to the number of boys who planned to participate in the trip was 10 : 9. On the day of registration, 78 boys decided to withdraw and 78 more girls decided to join in. In the end, the number of boys who participated became 20% of the total children for the trip. How many children would visit Brazil in the end?

	Girls	Boys	Total
Before	10x5 = 50 u	9x5 = 45 u	19x5 = 95 u
Change	+ 26 u	- 26 u
After	4x19 = 76 u	1x19 = 19 u	5x19 = 95 u

20% = ²⁰₁₀₀ = ¹₅

Since 78 boys withdrew and another 78 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 19 and 5 is 95.

Number of boys who decided to withdraw
= 45 u - 19 u
= 26 u

26 u = 78

1 u = 78 ÷ 26 = 3

Number of children that would visit Brazil in the end
= 76 u + 19 u
= 95 u
= 95 x 3
= 285

Answer(s): 285