In hospital wards, 1 bathtub or shower shall be provided per ____ patients.

The correct answer of 20 patients is based on healthcare standards and guidelines that aim to ensure adequate hygiene and sanitation facilities for patients in hospital settings. Providing one bathtub or shower for every 20 patients helps to balance accessibility with efficient use of space and resources.

This ratio allows for sufficient availability of bathing facilities to meet the personal hygiene needs of a large group of patients, which can be critical for infection control and overall patient comfort. If the ratio were set lower, for example, one for every 10 or 15 patients, it would require more space and resources than might be necessary, potentially leading to inefficiencies in hospital design. Conversely, a higher ratio, such as one shower for every 30 patients, might result in inadequate access, which could negatively impact patient care and hygiene.

Thus, the 20-patient guideline strikes a reasonable balance that can accommodate the needs of patients while maintaining an efficient layout and operational functionality within hospital environments.