Answer:
They will meet next at 6:03 pm
Step-by-step explanation:
Lixin, Khairul and Devi are at the starting point of a 1 km circular path at 5:45 pm.
We will convert time taken by each person in seconds for one round.
Lixin takes time to walk one round = 18 minutes = 18 × 60 = 1080 seconds.
Khairul completes one round in = 360 seconds
Devi completes two round in = 4 minutes = = 2 minutes = 120 seconds.
Time taken by each person for one round
Lixin = 1080 seconds
Khairul = 360 seconds
Devi = 120 seconds
Now use LCM ( Lowest common multiple ) to find the time when all three will next meet.
LCM of 1080, 360, 120
= 2 × 2 × 2 × 3 × 3 × 3 × 5
= 2³ × 3³ × 5 = 1080 seconds
= 18 minutes
After 18 minutes of 5:45 pm = 6:03 pm
They will meet next at 6:03 pm