Jamie's school organized a trip to Mexico. 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, 78 girls decided to withdraw and 78 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 more boys than girls would visit Mexico 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 78 girls withdrew and another 78 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 = 78
1 u = 78 ÷ 13 = 6
Number of more boys than girls in the end
= 45 u - 15 u
= 30 u
= 30 x 6
= 180
Answer(s): 180