PSLE On Monday, the number of adults to girls to boys visiting a zoo was 7 : 12 : 10. On Tuesday, the number of adults visiting the zoo remained the same. However, the number of girls decreased by 25% and the number of boys increased by 50%.
- What was the ratio of the number of children to adults visiting the zoo on Tuesday?
- On Monday, 748 girls and boys visited the zoo. What was the total number of child visitors at the zoo on Tuesday?
|
Adults |
Girls |
Boys |
Before |
7 u |
12 u |
10 u |
Change |
|
- 3 u |
+ 5 u |
After |
7 u |
9 u |
15 u |
(a)
Increase in the number of girls
= 25% x 12 u
=
25100 x 12 u
= 3 u
Decrease in the number of boys
= 50% x 10 u
=
50100 x 10 u
= 5 u
Number of girls on Tuesday
= 12 u - 3 u
= 9 u
Number of boys on Tuesday
= 10 u + 5 u
= 15 u
Number of children on Tuesday
= 9 u + 15 u
= 24 u
On Tuesday
Children : Adults
24 : 7
(b)
Number of girls and boys on Monday
= 12 u + 10 u
= 22 u
22 u = 748
1 u = 748 ÷ 22 = 34
Total number of child visitors on Tuesday
= 24 u
= 24 x 34
= 816
Answer(s): (a) 24 : 7; (b) 816