On pg 177 of your book it gives this question example and rule:
Thomas is baking pies for five friends M,N,O,P and R. Each pie will have at least one of six ingredients: F,G,H,J,K, and L. The following rules apply:
Possible rule 1: If a pie has F & G, it must also have J.
Then it states in the book the obvious, that if you have F & G -> J, but then it says you can’t have J without F & G, which is not what the rule says at all, and completely conflicts with the prior lesson/example.
If you know the pie has F & G then the rule states you must also have J. The rule doesn’t say that if you have J, you must have F & G?