PSLE At a swimathon, each participant completed either a 3-km route, a 4-km route or a 7-km route.
16 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, $7 was donated to charity. A total of $11340 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 -
16 -
49 = 1 -
318 -
818= 1 -
1118 =
718 Ratio of participants who completed the different routes
3 km : 4 km : 7 km
3 : 8 : 7
(b)
For every 1 km a participant swam, $7 was donated to charity.
Total distance covered by the participants
= 11340 ÷ 7
= 1620 km
|
3-km |
4-km |
7-km |
Total |
Number |
3 u |
8 u |
7 u |
18 u |
Value |
3 |
4 |
7 |
|
Total value |
9 u |
32 u |
49 u |
|
Total distance that the participants covered
= 3 x 3 u + 4 x 8 u + 7 x 7 u
= 9 u + 32 u + 49 u
= 90 u
90 u = 1620
1 u = 1620 ÷ 90 = 18
Total number of participants
= 3 u + 8 u + 7 u
= 18 u
= 18 x 18
= 324
Answer(s): (a) 3 : 8 : 7; (b) 324