PSLE At a swimathon, each participant completed either a 1-km route, a 3-km route or a 5-km route.
13 of the participants completed the 1-km route,
25 of the participants completed the 3-km route and the rest completed the 5-km route. For every 1 km a participant swam, $10 was donated to charity. A total of $7740 was donated to charity.
- What is the ratio of the number of participants who completed the 1-km route to the number who completed the 3-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 -
13 -
25 = 1 -
515 -
615= 1 -
1115 =
415 Ratio of participants who completed the different routes
1 km : 3 km : 5 km
5 : 6 : 4
(b)
For every 1 km a participant swam, $10 was donated to charity.
Total distance covered by the participants
= 7740 ÷ 10
= 774 km
|
1-km |
3-km |
5-km |
Total |
Number |
5 u |
6 u |
4 u |
15 u |
Value |
1 |
3 |
5 |
|
Total value |
5 u |
18 u |
20 u |
|
Total distance that the participants covered
= 1 x 5 u + 3 x 6 u + 5 x 4 u
= 5 u + 18 u + 20 u
= 43 u
43 u = 774
1 u = 774 ÷ 43 = 18
Total number of participants
= 5 u + 6 u + 4 u
= 15 u
= 15 x 18
= 270
Answer(s): (a) 5 : 6 : 4; (b) 270