Highly likely an error by the publisher. The number should be 0.015, or 1.5/100, to reflect that 3% per annum is equivalent to 1.5% per half year which is required here since the compounding frequency is twice a year.

Typically, I do not always trust given answers 100% of the time, after having experienced faults with many of them. Even Cambridge exams do make very rare errors (but they rectified it before I sat for one paper, in a very very rare occurrence more than ten years ago). You must take the answers given from this book with some degree of doubt.