PSLE At a swimathon, each participant completed either a 1-km route, a 2-km route or a 4-km route.
14 of the participants completed the 1-km route,
12 of the participants completed the 2-km route and the rest completed the 4-km route. For every 1 km a participant swam, $9 was donated to charity. A total of $1539 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 2-km route to the number who completed the 4-km route?
- What is the total number of participants at the swimathon?
(a)
Fraction of the participants who completed 4-km route
= 1 -
14 -
12 = 1 -
14 -
24= 1 -
34 =
14 Ratio of participants who completed the different routes
1 km : 2 km : 4 km
1 : 2 : 1
(b)
For every 1 km a participant swam, $9 was donated to charity.
Total distance covered by the participants
= 1539 ÷ 9
= 171 km
|
1-km |
2-km |
4-km |
Total |
Number |
1 u |
2 u |
1 u |
4 u |
Value |
1 |
2 |
4 |
|
Total value |
1 u |
4 u |
4 u |
|
Total distance that the participants covered
= 1 x 1 u + 2 x 2 u + 4 x 1 u
= 1 u + 4 u + 4 u
= 9 u
9 u = 171
1 u = 171 ÷ 9 = 19
Total number of participants
= 1 u + 2 u + 1 u
= 4 u
= 4 x 19
= 76
Answer(s): (a) 1 : 2 : 1; (b) 76