# LCM and GCF word problems | Factors and multiples | Pre-Algebra | Khan Academy | Summary and Q&A

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July 25, 2013
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LCM and GCF word problems | Factors and multiples | Pre-Algebra | Khan Academy

## TL;DR

Luis's class receives 30-question exams while William's class receives 24-question exams. The minimum number of questions they can expect in a year is 120.

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### Q: What is the minimum number of exams Luis's class can expect in a year?

Luis's class can expect a minimum of 4 exams in a year, with a total of 120 questions (30 questions per exam).

### Q: How many exams does William's class need to reach the minimum number of questions?

William's class needs 5 exams to reach the minimum number of 120 questions (24 questions per exam).

### Q: What do Luis and William's classes have in common regarding the number of exam questions?

Both classes can have the same total number of 120 exam questions, despite the different number of questions per exam.

### Q: How did the least common multiple (LCM) help find the minimum number of exam questions?

The LCM of 24 and 30 is 120, which represents the minimum number of exam questions that satisfies both Luis and William's classes.

## Summary & Key Takeaways

• Luis's class has 30-question exams and William's class has 24-question exams.

• The total number of exam questions for both classes in a year is the same.

• The minimum number of exam questions for both classes is 120.