PSLE At a swimathon, each participant completed either a 1-km route, a 3-km route or a 5-km route.
14 of the participants completed the 1-km route,
13 of the participants completed the 3-km route and the rest completed the 5-km route. For every 1 km a participant swam, $6 was donated to charity. A total of $2400 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 -
14 -
13 = 1 -
312 -
412= 1 -
712 =
512 Ratio of participants who completed the different routes
1 km : 3 km : 5 km
3 : 4 : 5
(b)
For every 1 km a participant swam, $6 was donated to charity.
Total distance covered by the participants
= 2400 ÷ 6
= 400 km
|
1-km |
3-km |
5-km |
Total |
Number |
3 u |
4 u |
5 u |
12 u |
Value |
1 |
3 |
5 |
|
Total value |
3 u |
12 u |
25 u |
|
Total distance that the participants covered
= 1 x 3 u + 3 x 4 u + 5 x 5 u
= 3 u + 12 u + 25 u
= 40 u
40 u = 400
1 u = 400 ÷ 40 = 10
Total number of participants
= 3 u + 4 u + 5 u
= 12 u
= 12 x 10
= 120
Answer(s): (a) 3 : 4 : 5; (b) 120