PSLE At a walkathon, each participant completed either a 2-km route, a 3-km route or a 4-km route.
25 of the participants completed the 2-km route,
815 of the participants completed the 3-km route and the rest completed the 4-km route. For every 1 km a participant walked, $8 was donated to charity. A total of $3200 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 3-km route to the number who completed the 4-km route?
- What is the total number of participants at the walkathon?
(a)
Fraction of the participants who completed 4-km route
= 1 -
25 -
815 = 1 -
615 -
815= 1 -
1415 =
115 Ratio of participants who completed the different routes
2 km : 3 km : 4 km
6 : 8 : 1
(b)
For every 1 km a participant walked, $8 was donated to charity.
Total distance covered by the participants
= 3200 ÷ 8
= 400 km
|
2-km |
3-km |
4-km |
Total |
Number |
6 u |
8 u |
1 u |
15 u |
Value |
2 |
3 |
4 |
|
Total value |
12 u |
24 u |
4 u |
|
Total distance that the participants covered
= 2 x 6 u + 3 x 8 u + 4 x 1 u
= 12 u + 24 u + 4 u
= 40 u
40 u = 400
1 u = 400 ÷ 40 = 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