PSLE At a swimathon, each participant completed either a 3-km route, a 6-km route or a 9-km route.
25 of the participants completed the 3-km route,
12 of the participants completed the 6-km route and the rest completed the 9-km route. For every 1 km a participant swam, $7 was donated to charity. A total of $4284 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 9-km route?
- What is the total number of participants at the swimathon?
(a)
Fraction of the participants who completed 9-km route
= 1 -
25 -
12 = 1 -
410 -
510= 1 -
910 =
110 Ratio of participants who completed the different routes
3 km : 6 km : 9 km
4 : 5 : 1
(b)
For every 1 km a participant swam, $7 was donated to charity.
Total distance covered by the participants
= 4284 ÷ 7
= 612 km
|
3-km |
6-km |
9-km |
Total |
Number |
4 u |
5 u |
1 u |
10 u |
Value |
3 |
6 |
9 |
|
Total value |
12 u |
30 u |
9 u |
|
Total distance that the participants covered
= 3 x 4 u + 6 x 5 u + 9 x 1 u
= 12 u + 30 u + 9 u
= 51 u
51 u = 612
1 u = 612 ÷ 51 = 12
Total number of participants
= 4 u + 5 u + 1 u
= 10 u
= 10 x 12
= 120
Answer(s): (a) 4 : 5 : 1; (b) 120