PSLE At a swimathon, each participant completed either a 1-km route, a 2-km route or a 3-km route.
25 of the participants completed the 1-km route,
815 of the participants completed the 2-km route and the rest completed the 3-km route. For every 1 km a participant swam, $7 was donated to charity. A total of $1750 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 3-km route?
- What is the total number of participants at the swimathon?
(a)
Fraction of the participants who completed 3-km route
= 1 -
25 -
815 = 1 -
615 -
815= 1 -
1415 =
115 Ratio of participants who completed the different routes
1 km : 2 km : 3 km
6 : 8 : 1
(b)
For every 1 km a participant swam, $7 was donated to charity.
Total distance covered by the participants
= 1750 ÷ 7
= 250 km
|
1-km |
2-km |
3-km |
Total |
Number |
6 u |
8 u |
1 u |
15 u |
Value |
1 |
2 |
3 |
|
Total value |
6 u |
16 u |
3 u |
|
Total distance that the participants covered
= 1 x 6 u + 2 x 8 u + 3 x 1 u
= 6 u + 16 u + 3 u
= 25 u
25 u = 250
1 u = 250 ÷ 25 = 10
Total number of participants
= 6 u + 8 u + 1 u
= 15 u
= 15 x 10
= 150
Answer(s): (a) 6 : 8 : 1; (b) 150