Answer:
When the problem cannot be solved in a reasonable time and an approximate solution is acceptable
Step-by-step explanation:
A heuristic is considered to be a mental shortcut which people use to solve problems by making judgement quickly and sometimes efficiently. It is a problem solving technique that makes use of a practical method that may or may not be optimal. Such technique is used when a problem is almost impossible to be solved within a reasonable time and a solution that closely solves the problem is acceptable.