Lucy's school organized a trip to India. At first, the ratio of the number of girls to the number of boys who planned to participate in the trip was 7 : 4. On the day of registration, 45 boys decided to withdraw and 45 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 more girls than boys would visit India in the end?

	Girls	Boys	Total
Before	7x5 = 35 u	4x5 = 20 u	11x5 = 55 u
Change	+ 9 u	- 9 u
After	4x11 = 44 u	1x11 = 11 u	5x11 = 55 u

20% = ²⁰₁₀₀ = ¹₅

Since 45 boys withdrew and another 45 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 11 and 5 is 55.

Number of boys who decided to withdraw
= 20 u - 11 u
= 9 u

9 u = 45

1 u = 45 ÷ 9 = 5

Number of more girls than boys in the end
= 44 u - 11 u
= 33 u
= 33 x 5
= 165

Answer(s): 165