PSLE At a swimathon, each participant completed either a 2-km route, a 5-km route or a 7-km route.
25 of the participants completed the 2-km route,
715 of the participants completed the 5-km route and the rest completed the 7-km route. For every 1 km a participant swam, $7 was donated to charity. A total of $6405 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 -
25 -
715 = 1 -
615 -
715= 1 -
1315 =
215 Ratio of participants who completed the different routes
2 km : 5 km : 7 km
6 : 7 : 2
(b)
For every 1 km a participant swam, $7 was donated to charity.
Total distance covered by the participants
= 6405 ÷ 7
= 915 km
|
2-km |
5-km |
7-km |
Total |
Number |
6 u |
7 u |
2 u |
15 u |
Value |
2 |
5 |
7 |
|
Total value |
12 u |
35 u |
14 u |
|
Total distance that the participants covered
= 2 x 6 u + 5 x 7 u + 7 x 2 u
= 12 u + 35 u + 14 u
= 61 u
61 u = 915
1 u = 915 ÷ 61 = 15
Total number of participants
= 6 u + 7 u + 2 u
= 15 u
= 15 x 15
= 225
Answer(s): (a) 6 : 7 : 2; (b) 225