PSLE On Thursday, the number of adults to girls to boys visiting a zoo was 5 : 8 : 12. On Friday, the number of adults visiting the zoo remained the same. However, the number of girls decreased by 50% and the number of boys increased by 50%.
- What was the ratio of the number of children to adults visiting the zoo on Friday?
- On Thursday, 800 girls and boys visited the zoo. What was the total number of child visitors at the zoo on Friday?
|
Adults |
Girls |
Boys |
Before |
5 u |
8 u |
12 u |
Change |
|
- 4 u |
+ 6 u |
After |
5 u |
4 u |
18 u |
(a)
Increase in the number of girls
= 50% x 8 u
=
50100 x 8 u
= 4 u
Decrease in the number of boys
= 50% x 12 u
=
50100 x 12 u
= 6 u
Number of girls on Friday
= 8 u - 4 u
= 4 u
Number of boys on Friday
= 12 u + 6 u
= 18 u
Number of children on Friday
= 4 u + 18 u
= 22 u
On Friday
Children : Adults
22 : 5
(b)
Number of girls and boys on Thursday
= 8 u + 12 u
= 20 u
20 u = 800
1 u = 800 ÷ 20 = 40
Total number of child visitors on Friday
= 22 u
= 22 x 40
= 880
Answer(s): (a) 22 : 5; (b) 880