I don't think anyone had mentioned this mistake yet....
The answer book for problem 9.1d says that the delta H for the reactants
is +152 kcal/mol, but it should be +150. The DH for methane is +104, and
the DH for BR-Br is +46, which is equal to a change of +150. The final
answer should then be -7.5 kcal/ mol, and not -5.5 kcal/mol.
ulamce