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Least Common Multiple (LCM)

In this topic, we learn to find the least common multiple (LCM) of a group of numbers by listing factors and using prime factorization.
Practice Question
1

Sam and his little brother are walking laps on a track. Sam walks one lap every 3 minutes, and his brother walks one lap every 5 minutes. They start together. In how many minutes will they be together at the starting line again?

 
Possible Answers
Your Answer
Correct Answer
A)

15
B)

20
C)

10
D)

5
Practice Question
2

Hanna and her dad are walking around the track. Hanna completes one lap every 10 minutes. Her dad completes one lap every 8 minutes. They start together. In how many minutes will they be together at the starting line again?

 
Possible Answers
Your Answer
Correct Answer
A)

80
B)

20
C)

40
D)

45
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