A math teacher wishes to use groups of 5 and/or 7 students for a class assignment. When she tries to make assignments she notices that it cannot be done with the number of students in her class. However, if the number of students were any larger, the assignments could be made. How many students does the teacher have?

Answer 1

Let's look at the multiples of these numbers.

5, 10, 15, 20, 25, 30, 35, 40
7, 14, 21, 28, 35, 42, 49

The LCM is 35

Do you suppose that the teacher has 34 in the class?