Question

At 5.45pm, lixin, khairul and devi are at the starting point of a 1km circular path. Lixin takes 18 minutes to walk one round. Khairul needs 360 seconds to run 1 round and devi cycles 2 rounds in 4 minutes. Find the time when all three of them will next meet.

Answer 1

here you go 
hope this helps

Answer 2

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 = $\frac{4}{2}$ = 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

$\frac{1080}{60}$ = 18 minutes

After 18 minutes of 5:45 pm = 6:03 pm

They will meet next at 6:03 pm