PSLE At a swimathon, each participant completed either a 3-km route, a 6-km route or a 8-km route.
25 of the participants completed the 3-km route,
715 of the participants completed the 6-km route and the rest completed the 8-km route. For every 1 km a participant swam, $9 was donated to charity. A total of $12312 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 6-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 -
25 -
715 = 1 -
615 -
715= 1 -
1315 =
215 Ratio of participants who completed the different routes
3 km : 6 km : 8 km
6 : 7 : 2
(b)
For every 1 km a participant swam, $9 was donated to charity.
Total distance covered by the participants
= 12312 ÷ 9
= 1368 km
|
3-km |
6-km |
8-km |
Total |
Number |
6 u |
7 u |
2 u |
15 u |
Value |
3 |
6 |
8 |
|
Total value |
18 u |
42 u |
16 u |
|
Total distance that the participants covered
= 3 x 6 u + 6 x 7 u + 8 x 2 u
= 18 u + 42 u + 16 u
= 76 u
76 u = 1368
1 u = 1368 ÷ 76 = 18
Total number of participants
= 6 u + 7 u + 2 u
= 15 u
= 15 x 18
= 270
Answer(s): (a) 6 : 7 : 2; (b) 270