PSLE On Thursday, the number of adults to girls to boys visiting a bird park was 5 : 4 : 5. On Friday, the number of adults visiting the bird park remained the same. However, the number of girls decreased by 25% and the number of boys increased by 20%.
- What was the ratio of the number of children to adults visiting the bird park on Friday?
- On Thursday, 441 girls and boys visited the bird park. What was the total number of child visitors at the bird park on Friday?
|
Adults |
Girls |
Boys |
Before |
5 u |
4 u |
5 u |
Change |
|
- 1 u |
+ 1 u |
After |
5 u |
3 u |
6 u |
(a)
Increase in the number of girls
= 25% x 4 u
=
25100 x 4 u
= 1 u
Decrease in the number of boys
= 20% x 5 u
=
20100 x 5 u
= 1 u
Number of girls on Friday
= 4 u - 1 u
= 3 u
Number of boys on Friday
= 5 u + 1 u
= 6 u
Number of children on Friday
= 3 u + 6 u
= 9 u
On Friday
Children : Adults
9 : 5
(b)
Number of girls and boys on Thursday
= 4 u + 5 u
= 9 u
9 u = 441
1 u = 441 ÷ 9 = 49
Total number of child visitors on Friday
= 9 u
= 9 x 49
= 441
Answer(s): (a) 9 : 5; (b) 441