Leanne runs a lap in 12 minutes. Kory runs a lap in 9 minutes. If they
both start running at 10 am, at what time will they both cross the start
together again?

Kory and Leanne will meet each other again after 36 minutes from starting i.e. at 10:36 am .

Step-by-step explanation:

Here we have , Leanne runs a lap in 12 minutes. Kory runs a lap in 9 minutes. We need to find out that If they  both start running at 10 am, at what time will they both cross the start  together again . Let's find out:

Kory runs a lap in 9 minutes and , Leanne in 12 minutes , in order to find at what time will they both cross the start  together again we will find LCM of 9 & 12 :

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So ,LCM of 9 & 12 is 36 .That means Kory and Leanne will meet each other again after 36 minutes from starting i.e. at 10:36 am .

In clear way , Kory will run race as :

1st lap = 9 minutes

2nd lap = 18 minutes

3rd lap = 27 minutes

4th lap = 36 minutes , i.e. at 10:36 am he'll complete his 4th lap

For , Leanne

1st lap = 12 minutes

2nd lap = 24 minutes

3rd lap = 36 minutes i.e. at 10:36 am he'll complete his 3rd lap .

This means Kory & Leanne will meet at 10:36 am completing there 4th and 3rd lap respectively .