PSLE At a swimathon, each participant completed either a 3-km route, a 4-km route or a 7-km route.
13 of the participants completed the 3-km route,
49 of the participants completed the 4-km route and the rest completed the 7-km route. For every 1 km a participant swam, $6 was donated to charity. A total of $3978 was donated to charity.
- What is the ratio of the number of participants who completed the 3-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 -
49 = 1 -
39 -
49= 1 -
79 =
29 Ratio of participants who completed the different routes
3 km : 4 km : 7 km
3 : 4 : 2
(b)
For every 1 km a participant swam, $6 was donated to charity.
Total distance covered by the participants
= 3978 ÷ 6
= 663 km
|
3-km |
4-km |
7-km |
Total |
Number |
3 u |
4 u |
2 u |
9 u |
Value |
3 |
4 |
7 |
|
Total value |
9 u |
16 u |
14 u |
|
Total distance that the participants covered
= 3 x 3 u + 4 x 4 u + 7 x 2 u
= 9 u + 16 u + 14 u
= 39 u
39 u = 663
1 u = 663 ÷ 39 = 17
Total number of participants
= 3 u + 4 u + 2 u
= 9 u
= 9 x 17
= 153
Answer(s): (a) 3 : 4 : 2; (b) 153