Ryan's school organized a trip to Spain. 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, 42 boys decided to withdraw and 42 more girls decided to join in. In the end, the number of boys who participated became 40% of the total children for the trip. How many less boys than girls would visit Spain in the end?

	Girls	Boys	Total
Before	10x5 = 50 u	9x5 = 45 u	19x5 = 95 u
Change	+ 7 u	- 7 u
After	3x19 = 57 u	2x19 = 38 u	5x19 = 95 u

40% = ⁴⁰₁₀₀ = ²₅

Since 42 boys withdrew and another 42 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 - 38 u
= 7 u

7 u = 42

1 u = 42 ÷ 7 = 6

Number of less boys than girls in the end
= 57 u - 38 u
= 19 u
= 19 x 6
= 114

Answer(s): 114