In binary search, if the middle element is greater than the key, search the:

1. The list is in order, so everything after the middle is larger still. 2. The key can only lie before the middle. 3. If the middle element is greater than the key, the key must be in the first half. 4. So the answer is the first half. _Source: syllabus Computer Science, Ch 5 'Sorting' and Ch 6 'Searching'_