Lucy's school organized a trip to Mexico. 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, 133 boys decided to withdraw and 133 more girls decided to join in. In the end, the number of boys who participated became 10% of the total children for the trip. How many less boys than girls would visit Mexico in the end?

	Girls	Boys	Total
Before	7x5 = 35 u	5x5 = 25 u	12x5 = 60 u
Change	+ 19 u	- 19 u
After	9x6 = 54 u	1x6 = 6 u	10x6 = 60 u

10% = ¹⁰₁₀₀ = ¹₁₀

Since 133 boys withdrew and another 133 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 10 is 60.

Number of boys who decided to withdraw
= 25 u - 6 u
= 19 u

19 u = 133

1 u = 133 ÷ 19 = 7

Number of less boys than girls in the end
= 54 u - 6 u
= 48 u
= 48 x 7
= 336

Answer(s): 336