Mason's school organized a trip to Italy. At first, the ratio of the number of boys to the number of girls who planned to participate in the trip was 10 : 9. On the day of registration, 153 girls decided to withdraw and 153 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 less girls than boys would visit Italy in the end?

	Boys	Girls	Total
Before	10x4 = 40 u	9x4 = 36 u	19x4 = 76 u
Change	+ 17 u	- 17 u
After	3x19 = 57 u	1x19 = 19 u	4x19 = 76 u

25% = ²⁵₁₀₀ = ¹₄

Since 153 girls withdrew and another 153 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 19 and 4 is 76.

Number of girls who decided to withdraw
= 36 u - 19 u
= 17 u

17 u = 153

1 u = 153 ÷ 17 = 9

Number of less girls than boys in the end
= 57 u - 19 u
= 38 u
= 38 x 9
= 342

Answer(s): 342