Lilian's school organized a trip to Vietnam. At first, the ratio of the number of boys to the number of girls who planned to participate in the trip was 8 : 7. On the day of registration, 117 girls decided to withdraw and 117 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 Vietnam in the end?
|
Boys |
Girls |
Total |
Before |
8x4 = 32 u |
7x4 = 28 u |
15x4 = 60 u |
Change |
+ 13 u |
- 13 u |
|
After |
3x15 = 45 u |
1x15 = 15 u |
4x15 = 60 u |
25% =
25100 =
14Since 117 girls withdrew and another 117 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 15 and 4 is 60.
Number of girls who decided to withdraw
= 28 u - 15 u
= 13 u
13 u = 117
1 u = 117 ÷ 13 = 9
Number of less girls than boys in the end
= 45 u - 15 u
= 30 u
= 30 x 9
= 270
Answer(s): 270