Calculate the standard enthalpy change for the reaction

Question

2A+B⇌2C+2D
Use the following data:
Substance ΔH∘f
(kJ/mol)
A -247
B -375
C 191
D -483
Express your answer to three significant figures and include the appropriate units.

My answer was 285 kJ/mol but mastering Chemistry says i was wrong

Answer 1

I agree with you.Book must be wrong.