Matthew's school organized a trip to Greece. 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, 32 girls decided to withdraw and 32 more boys decided to join in. In the end, the number of girls who participated became 20% of the total children for the trip. How many less girls than boys would visit Greece in the end?
|
Boys |
Girls |
Total |
Before |
8x1 = 8 u |
7x1 = 7 u |
15x1 = 15 u |
Change |
+ 4 u |
- 4 u |
|
After |
4x3 = 12 u |
1x3 = 3 u |
5x3 = 15 u |
20% =
20100 =
15Since 32 girls withdrew and another 32 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 5 is 15.
Number of girls who decided to withdraw
= 7 u - 3 u
= 4 u
4 u = 32
1 u = 32 ÷ 4 = 8
Number of less girls than boys in the end
= 12 u - 3 u
= 9 u
= 9 x 8
= 72
Answer(s): 72