Question

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?​

Answer 1

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 :

⇒ $\frac{9(4)}{12(4)}$

⇒ $\frac{36}{36}$

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 .