PSLE At a swimathon, each participant completed either a 3-km route, a 4-km route or a 5-km route.
15 of the participants completed the 3-km route,
12 of the participants completed the 4-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 $6642 was donated to charity.
- What is the ratio of the number of participants who completed the 3-km route to the number who completed the 4-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 -
15 -
12 = 1 -
210 -
510= 1 -
710 =
310 Ratio of participants who completed the different routes
3 km : 4 km : 5 km
2 : 5 : 3
(b)
For every 1 km a participant swam, $9 was donated to charity.
Total distance covered by the participants
= 6642 ÷ 9
= 738 km
|
3-km |
4-km |
5-km |
Total |
Number |
2 u |
5 u |
3 u |
10 u |
Value |
3 |
4 |
5 |
|
Total value |
6 u |
20 u |
15 u |
|
Total distance that the participants covered
= 3 x 2 u + 4 x 5 u + 5 x 3 u
= 6 u + 20 u + 15 u
= 41 u
41 u = 738
1 u = 738 ÷ 41 = 18
Total number of participants
= 2 u + 5 u + 3 u
= 10 u
= 10 x 18
= 180
Answer(s): (a) 2 : 5 : 3; (b) 180