Question

Three joggers are running around a circular track. One of them completes one lap in 6 minutes, the second one in 9 minutes, and the third one in 15 minutes. What time will they arrive at their starting point together if they start at the same time from the same point at 10:00 am and maintain their jogging pace

Answer 1

At 11:30 am they will arrive at their starting point together

Explanation:

we know that

One of them completes one lap in 6 minutes

The second one in 9 minutes

The third one in 15 minutes

step 1

Find the least common multiple (LCM)

6=2*3

9=3²

15=3*5

so

LCM=(3²)*(2)*(5)=90 minutes

step 2

Find the number of laps of each jogger for the LCM

jogger 1

90/6=15 laps

jogger 2

90/9=10 laps

jogger 3

90/15=6 laps

If they start at 10:00 am

then

10:00 am + 90 minutes=11:30 am