Luis, Vincent and Will started walking at the same time from the same starting point round a circular track. Will walked in the clockwise direction. Luis and Vincent walked in an anti-clockwise direction. Will took 6 min to complete each round. He met Luis after every 2 minutes. He met Vincent after every 4 minutes. The three friends kept to their respective speeds throughout their walk.
- How many rounds did Will complete in 1 h?
- When Will and Luis met again at the starting point after 1 h, Vincent had completed 2.6 km. Find the circumference of the circular track in metres.
(a)
1 h = 60 min
Number of rounds that Will completed in 1 h
= 60 ÷ 6
= 10
(b)
Will took 6 min to complete 1 round
1 min =
16 of circular track = 1 u
6 min =
66 of circular track = 6 u
Will's distance is the repeated identity.
Make Will's distance the same.
Will's distance : Luis's distance
2 : 6 - 2
2 : 4
Will's distance : Vincent's distance
4 : 6 - 4
4 : 2
Will |
Luis |
Vincent |
2x2 |
4x2 |
|
4x1 |
|
2x1 |
4 |
8 |
2 |
The distance of Will is the repeated identity.
LCM of 2 and 4 = 4
In 1 h
Will's rounds : Luis's rounds : Vincent's rounds
4 : 8 : 2
Distance that Vincent completed in 1 h = 2.6 km
2 rounds = 2.6 km = 2600 m
1 round = 2600 ÷ 2 = 1300 m
Circumference of the circular track = 1300 m
Answer(s): (a) 10; (b) 1300 m