Logic games workbook page 29 grouping setup practice

[destaat]

#4 about senators and subcommittees:

How do I know that any one of the senators don't serve on a subcommittee. I struggle when reading the game rules to know when variables MUSt be included unless they explicitly say something like each senator must serve on exactly one committee.

In this case regarding the "j if and only if m" rule, Im not sure whether its possible that neither are included and other senators serve on more than one committee.

[Dave Killoran]

Hi A.T.,

The way you know this is in the first line: "Eight senators...serve on three subcommittees." This is classic LSAC wording, and the idea being conveyed is that all eight are indeed serving (if it was the case that a senator did not have to serve, it would be made clear elsewhere). Consequently, the "if and only if" rule then means they both serve together.

Please let me know if that helps. Thanks!