PSLE At a swimathon, each participant completed either a 2-km route, a 3-km route or a 5-km route.
16 of the participants completed the 2-km route,
712 of the participants completed the 3-km route and the rest completed the 5-km route. For every 1 km a participant swam, $9 was donated to charity. A total of $7200 was donated to charity.
- What is the ratio of the number of participants who completed the 2-km route to the number who completed the 3-km route to the number who completed the 5-km route?
- What is the total number of participants at the swimathon?
(a)
Fraction of the participants who completed 5-km route
= 1 -
16 -
712 = 1 -
212 -
712= 1 -
912 =
312 Ratio of participants who completed the different routes
2 km : 3 km : 5 km
2 : 7 : 3
(b)
For every 1 km a participant swam, $9 was donated to charity.
Total distance covered by the participants
= 7200 ÷ 9
= 800 km
|
2-km |
3-km |
5-km |
Total |
Number |
2 u |
7 u |
3 u |
12 u |
Value |
2 |
3 |
5 |
|
Total value |
4 u |
21 u |
15 u |
|
Total distance that the participants covered
= 2 x 2 u + 3 x 7 u + 5 x 3 u
= 4 u + 21 u + 15 u
= 40 u
40 u = 800
1 u = 800 ÷ 40 = 20
Total number of participants
= 2 u + 7 u + 3 u
= 12 u
= 12 x 20
= 240
Answer(s): (a) 2 : 7 : 3; (b) 240