PSLE On Wednesday, the number of adults to girls to boys visiting a zoo was 1 : 10 : 6. On Thursday, 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 Thursday?
- On Wednesday, 480 girls and boys visited the zoo. What was the total number of child visitors at the zoo on Thursday?
|
Adults |
Girls |
Boys |
Before |
1 u |
10 u |
6 u |
Change |
|
- 5 u |
+ 3 u |
After |
1 u |
5 u |
9 u |
(a)
Increase in the number of girls
= 50% x 10 u
=
50100 x 10 u
= 5 u
Decrease in the number of boys
= 50% x 6 u
=
50100 x 6 u
= 3 u
Number of girls on Thursday
= 10 u - 5 u
= 5 u
Number of boys on Thursday
= 6 u + 3 u
= 9 u
Number of children on Thursday
= 5 u + 9 u
= 14 u
On Thursday
Children : Adults
14 : 1
(b)
Number of girls and boys on Wednesday
= 10 u + 6 u
= 16 u
16 u = 480
1 u = 480 ÷ 16 = 30
Total number of child visitors on Thursday
= 14 u
= 14 x 30
= 420
Answer(s): (a) 14 : 1; (b) 420