PSLE On Friday, the number of adults to boys to girls visiting a zoo was 5 : 4 : 10. On Saturday, the number of adults visiting the zoo remained the same. However, the number of boys increased by 50% and the number of girls decreased by 40%.
- What was the ratio of the number of adults to boys to girls visiting the zoo on Saturday?
- On Friday, 280 boys and girls visited the zoo. What was the total number of visitors at the zoo on Saturday?
|
Adults |
Boys |
Girls |
Before |
5 u |
4 u |
10 u |
Change |
|
+ 2 u |
- 4 u |
After |
5 u |
6 u |
6 u |
(a)
Increase in the number of boys
= 50% x 4 u
=
50100 x 4 u
= 2 u
Decrease in the number of girls
= 40% x 10 u
=
40100 x 10 u
= 4 u
Number of boys on Saturday
= 4 u + 2 u
= 6 u
Number of girls on Saturday
= 10 u - 4 u
= 6 u
On Saturday
Adults : Boys : Girls
5 : 6 : 6
(b)
Number of boys and girls on Friday
= 4 u + 10 u
= 14 u
14 u = 280
1 u = 280 ÷ 14 = 20
Total number of visitors on Saturday
= 5 u + 6 u + 6 u
= 17 u
= 17 x 20
= 340
Answer(s): (a) 5 : 6 : 6; (b) 340