The LCM stands for the least common multiple. The least of the possible number of choir members at the rehearsal is 59.
The least common multiple that is divisible by both a and b is the smallest positive integer, lowest common multiple, or smallest common multiple of two numbers a and b, generally indicated by LCM.
Given the configurations of choir members at the rehearsal, which are,
Now, it takes the LCM of 12, 15, and 20, then the LCM will be 60, But since None of these configurations worked because for each, the last row had 1 person less than the other rows. The number of members was 1 less than the LCM.
Hence, the least of the possible number of choir members at the rehearsal is 59.
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