PSLE At a walkathon, each participant completed either a 2-km route, a 5-km route or a 7-km route.
13 of the participants completed the 2-km route,
712 of the participants completed the 5-km route and the rest completed the 7-km route. For every 1 km a participant walked, $5 was donated to charity. A total of $2500 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 -
13 -
712 = 1 -
412 -
712= 1 -
1112 =
112 Ratio of participants who completed the different routes
2 km : 5 km : 7 km
4 : 7 : 1
(b)
For every 1 km a participant walked, $5 was donated to charity.
Total distance covered by the participants
= 2500 ÷ 5
= 500 km
|
2-km |
5-km |
7-km |
Total |
Number |
4 u |
7 u |
1 u |
12 u |
Value |
2 |
5 |
7 |
|
Total value |
8 u |
35 u |
7 u |
|
Total distance that the participants covered
= 2 x 4 u + 5 x 7 u + 7 x 1 u
= 8 u + 35 u + 7 u
= 50 u
50 u = 500
1 u = 500 ÷ 50 = 10
Total number of participants
= 4 u + 7 u + 1 u
= 12 u
= 12 x 10
= 120
Answer(s): (a) 4 : 7 : 1; (b) 120