PSLE At a swimathon, each participant completed either a 2-km route, a 5-km route or a 7-km route.
12 of the participants completed the 2-km route,
514 of the participants completed the 5-km route and the rest completed the 7-km route. For every 1 km a participant swam, $5 was donated to charity. A total of $2650 was donated to charity.
- What is the ratio of the number of participants who completed the 2-km route to the number who completed the 5-km route to the number who completed the 7-km route?
- What is the total number of participants at the swimathon?
(a)
Fraction of the participants who completed 7-km route
= 1 -
12 -
514 = 1 -
714 -
514= 1 -
1214 =
214 Ratio of participants who completed the different routes
2 km : 5 km : 7 km
7 : 5 : 2
(b)
For every 1 km a participant swam, $5 was donated to charity.
Total distance covered by the participants
= 2650 ÷ 5
= 530 km
|
2-km |
5-km |
7-km |
Total |
Number |
7 u |
5 u |
2 u |
14 u |
Value |
2 |
5 |
7 |
|
Total value |
14 u |
25 u |
14 u |
|
Total distance that the participants covered
= 2 x 7 u + 5 x 5 u + 7 x 2 u
= 14 u + 25 u + 14 u
= 53 u
53 u = 530
1 u = 530 ÷ 53 = 10
Total number of participants
= 7 u + 5 u + 2 u
= 14 u
= 14 x 10
= 140
Answer(s): (a) 7 : 5 : 2; (b) 140