PSLE At a walkathon, each participant completed either a 3-km route, a 5-km route or a 7-km route.
14 of the participants completed the 3-km route,
12 of the participants completed the 5-km route and the rest completed the 7-km route. For every 1 km a participant walked, $9 was donated to charity. A total of $3420 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 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 -
14 -
12 = 1 -
14 -
24= 1 -
34 =
14 Ratio of participants who completed the different routes
3 km : 5 km : 7 km
1 : 2 : 1
(b)
For every 1 km a participant walked, $9 was donated to charity.
Total distance covered by the participants
= 3420 ÷ 9
= 380 km
|
3-km |
5-km |
7-km |
Total |
Number |
1 u |
2 u |
1 u |
4 u |
Value |
3 |
5 |
7 |
|
Total value |
3 u |
10 u |
7 u |
|
Total distance that the participants covered
= 3 x 1 u + 5 x 2 u + 7 x 1 u
= 3 u + 10 u + 7 u
= 20 u
20 u = 380
1 u = 380 ÷ 20 = 19
Total number of participants
= 1 u + 2 u + 1 u
= 4 u
= 4 x 19
= 76
Answer(s): (a) 1 : 2 : 1; (b) 76