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,
34 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 $12474 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 -
34 = 1 -
420 -
1520= 1 -
1920 =
120 Ratio of participants who completed the different routes
3 km : 4 km : 5 km
4 : 15 : 1
(b)
For every 1 km a participant swam, $9 was donated to charity.
Total distance covered by the participants
= 12474 ÷ 9
= 1386 km
|
3-km |
4-km |
5-km |
Total |
Number |
4 u |
15 u |
1 u |
20 u |
Value |
3 |
4 |
5 |
|
Total value |
12 u |
60 u |
5 u |
|
Total distance that the participants covered
= 3 x 4 u + 4 x 15 u + 5 x 1 u
= 12 u + 60 u + 5 u
= 77 u
77 u = 1386
1 u = 1386 ÷ 77 = 18
Total number of participants
= 4 u + 15 u + 1 u
= 20 u
= 20 x 18
= 360
Answer(s): (a) 4 : 15 : 1; (b) 360