PSLE At a walkathon, each participant completed either a 2-km route, a 5-km route or a 7-km route.
23 of the participants completed the 2-km route,
14 of the participants completed the 5-km route and the rest completed the 7-km route. For every 1 km a participant walked, $10 was donated to charity. A total of $3800 was donated to charity.
- What is the ratio of the number of participants who completed the 2-km route to the number who completed the 5-km route to the number who completed the 7-km route?
- What is the total number of participants at the walkathon?
(a)
Fraction of the participants who completed 7-km route
= 1 -
23 -
14 = 1 -
812 -
312= 1 -
1112 =
112 Ratio of participants who completed the different routes
2 km : 5 km : 7 km
8 : 3 : 1
(b)
For every 1 km a participant walked, $10 was donated to charity.
Total distance covered by the participants
= 3800 ÷ 10
= 380 km
|
2-km |
5-km |
7-km |
Total |
Number |
8 u |
3 u |
1 u |
12 u |
Value |
2 |
5 |
7 |
|
Total value |
16 u |
15 u |
7 u |
|
Total distance that the participants covered
= 2 x 8 u + 5 x 3 u + 7 x 1 u
= 16 u + 15 u + 7 u
= 38 u
38 u = 380
1 u = 380 ÷ 38 = 10
Total number of participants
= 8 u + 3 u + 1 u
= 12 u
= 12 x 10
= 120
Answer(s): (a) 8 : 3 : 1; (b) 120