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,
715 of the participants completed the 4-km route and the rest completed the 7-km route. For every 1 km a participant swam, $9 was donated to charity. A total of $18648 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 -
715 = 1 -
530 -
1430= 1 -
1930 =
1130 Ratio of participants who completed the different routes
3 km : 4 km : 7 km
5 : 14 : 11
(b)
For every 1 km a participant swam, $9 was donated to charity.
Total distance covered by the participants
= 18648 ÷ 9
= 2072 km
|
3-km |
4-km |
7-km |
Total |
Number |
5 u |
14 u |
11 u |
30 u |
Value |
3 |
4 |
7 |
|
Total value |
15 u |
56 u |
77 u |
|
Total distance that the participants covered
= 3 x 5 u + 4 x 14 u + 7 x 11 u
= 15 u + 56 u + 77 u
= 148 u
148 u = 2072
1 u = 2072 ÷ 148 = 14
Total number of participants
= 5 u + 14 u + 11 u
= 30 u
= 30 x 14
= 420
Answer(s): (a) 5 : 14 : 11; (b) 420