PSLE At a swimathon, each participant completed either a 1-km route, a 4-km route or a 7-km route.
13 of the participants completed the 1-km route,
815 of the participants completed the 4-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 $4641 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 4-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 -
13 -
815 = 1 -
515 -
815= 1 -
1315 =
215 Ratio of participants who completed the different routes
1 km : 4 km : 7 km
5 : 8 : 2
(b)
For every 1 km a participant swam, $7 was donated to charity.
Total distance covered by the participants
= 4641 ÷ 7
= 663 km
|
1-km |
4-km |
7-km |
Total |
Number |
5 u |
8 u |
2 u |
15 u |
Value |
1 |
4 |
7 |
|
Total value |
5 u |
32 u |
14 u |
|
Total distance that the participants covered
= 1 x 5 u + 4 x 8 u + 7 x 2 u
= 5 u + 32 u + 14 u
= 51 u
51 u = 663
1 u = 663 ÷ 51 = 13
Total number of participants
= 5 u + 8 u + 2 u
= 15 u
= 15 x 13
= 195
Answer(s): (a) 5 : 8 : 2; (b) 195