PSLE At a swimathon, each participant completed either a 1-km route, a 2-km route or a 5-km route.
12 of the participants completed the 1-km route,
15 of the participants completed the 2-km route and the rest completed the 5-km route. For every 1 km a participant swam, $10 was donated to charity. A total of $3600 was donated to charity.
- What is the ratio of the number of participants who completed the 1-km route to the number who completed the 2-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 -
12 -
15 = 1 -
510 -
210= 1 -
710 =
310 Ratio of participants who completed the different routes
1 km : 2 km : 5 km
5 : 2 : 3
(b)
For every 1 km a participant swam, $10 was donated to charity.
Total distance covered by the participants
= 3600 ÷ 10
= 360 km
|
1-km |
2-km |
5-km |
Total |
Number |
5 u |
2 u |
3 u |
10 u |
Value |
1 |
2 |
5 |
|
Total value |
5 u |
4 u |
15 u |
|
Total distance that the participants covered
= 1 x 5 u + 2 x 2 u + 5 x 3 u
= 5 u + 4 u + 15 u
= 24 u
24 u = 360
1 u = 360 ÷ 24 = 15
Total number of participants
= 5 u + 2 u + 3 u
= 10 u
= 10 x 15
= 150
Answer(s): (a) 5 : 2 : 3; (b) 150