PSLE At a swimathon, each participant completed either a 3-km route, a 5-km route or a 8-km route.
15 of the participants completed the 3-km route,
310 of the participants completed the 5-km route and the rest completed the 8-km route. For every 1 km a participant swam, $10 was donated to charity. A total of $7320 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 5-km route to the number who completed the 8-km route?
- What is the total number of participants at the swimathon?
(a)
Fraction of the participants who completed 8-km route
= 1 -
15 -
310 = 1 -
210 -
310= 1 -
510 =
510 Ratio of participants who completed the different routes
3 km : 5 km : 8 km
2 : 3 : 5
(b)
For every 1 km a participant swam, $10 was donated to charity.
Total distance covered by the participants
= 7320 ÷ 10
= 732 km
|
3-km |
5-km |
8-km |
Total |
Number |
2 u |
3 u |
5 u |
10 u |
Value |
3 |
5 |
8 |
|
Total value |
6 u |
15 u |
40 u |
|
Total distance that the participants covered
= 3 x 2 u + 5 x 3 u + 8 x 5 u
= 6 u + 15 u + 40 u
= 61 u
61 u = 732
1 u = 732 ÷ 61 = 12
Total number of participants
= 2 u + 3 u + 5 u
= 10 u
= 10 x 12
= 120
Answer(s): (a) 2 : 3 : 5; (b) 120