PSLE On Friday, the number of adults to girls to boys visiting a zoo was 1 : 10 : 6. On Saturday, the number of adults visiting the zoo remained the same. However, the number of girls increased by 20% and the number of boys decreased by 50%.
- What was the ratio of the number of adults to girls to boys visiting the zoo on Saturday?
- On Friday, 768 girls and boys visited the zoo. What was the total number of visitors at the zoo on Saturday?
|
Adults |
Girls |
Boys |
Before |
1 u |
10 u |
6 u |
Change |
|
+ 2 u |
- 3 u |
After |
1 u |
12 u |
3 u |
(a)
Increase in the number of girls
= 20% x 10 u
=
20100 x 10 u
= 2 u
Decrease in the number of boys
= 50% x 6 u
=
50100 x 6 u
= 3 u
Number of girls on Saturday
= 10 u + 2 u
= 12 u
Number of boys on Saturday
= 6 u - 3 u
= 3 u
On Saturday
Adults : Girls : Boys
1 : 12 : 3
(b)
Number of girls and boys on Friday
= 10 u + 6 u
= 16 u
16 u = 768
1 u = 768 ÷ 16 = 48
Total number of visitors on Saturday
= 1 u + 12 u + 3 u
= 16 u
= 16 x 48
= 768
Answer(s): (a) 1 : 12 : 3; (b) 768