Two bike riders ride around a circular path, the first rider completes one round in 12 minutes and the second rider completes it in 18 minutes. If they both start at the same place and at the same time and go in the same direction, after how many minutes will they meet again at the starting place?

Question

anonymous · Answer

so doesayone have an answer? :)

anonymous · Answer

36

anonymous · Answer

but like do u have a detailed answer pls

anonymous · Answer

by the time the second rider completes one lap, the first rider is halfway through his second lap. 18-12=6. 6 is 1/2 of 12 so the first rider is halfway through the course. So when the second rider completes his second lap (36 minutes) the first rider has completed 3 laps. 36-12-12-12=0. In other words, they're both at the starting point at the 36th minute.

anonymous · Answer

That was a bad explanation let me try again.

mathstudent55 · Answer

You need the least common multiple of 12 and 18.
One way to find the LCM is list several multiples of each number and find the smallest multiple they have in common.

mathstudent55 · Answer

Multiples of 12: 12, 24, 36, 48, 60, 72, ...
Multiples of 18: 18, 36, 54, 72, ...
What is the smallest multiple common to both 12 and 18?

anonymous · Answer

For this question, you basically want to find the least common multiple. This is because you're looking for when they both meet up at the starting point. The second guy gets to the starting point in multiples of 18 while the first gets there in multiples of 12.

anonymous · Answer

ahhh thanks you guys u really saved me there :)