Drafting the Duty Roster With Four Constraints
A security supervisor must post four guards - A, B, C and D - to four posts for a single day shift at an RBI office. The posts are Main Gate (MG), the Currency Chest corridor (CC), the Control Room (CR) and the Visitor Lobby (VL). The following conditions apply.
Only A and C hold fire-safety certification, and the Control Room post may be manned only by a certified guard. Only C has completed currency-chest sensitivity training, and the CC post requires it. B carries a medical note stating that he must not stand continuously for more than two hours; the Main Gate is a standing post for the whole shift, while the Visitor Lobby is a seated post. D has not completed visitor-verification training, so D cannot be posted to the Visitor Lobby. Each guard holds exactly one post for the shift, and no post may be left unmanned.
The supervisor also learns that A has reported sick and will not come, and that a substitute, E, has arrived with no fire-safety certification and no chest training.
1. Using only the four original guards A, B, C and D, work out the posting and show why no other arrangement is possible.
Read the worked answer
Step 1 - the most restricted post first. CC accepts only C (the sole chest-trained guard). So C is fixed at CC. Nothing else can move him.
Step 2 - the next most restricted post. CR needs A or C. C is already committed, so A must take CR. A is now fixed.
Step 3 - the remaining two posts. MG and VL are left for B and D. D cannot take VL, so D must take MG. B therefore takes VL, which suits his medical note because the lobby is seated.
Final posting: A - Control Room; C - Currency Chest corridor; D - Main Gate; B - Visitor Lobby.
The arrangement is unique because each step was forced. Any swap breaks a rule: C to CR leaves CC unmanned by a trained guard; A to MG leaves CR without certification; D to VL breaches the training requirement; B to MG breaches the medical restriction. A roster is only defensible when each placement can be traced to a stated condition.
2. With A absent and only E available, what can the supervisor do, and what must he not do?
Read the worked answer
The conflict. CR can be manned only by a fire-certified guard, and the only certified guard present is C. But CC can be manned only by C as well. One guard cannot hold two posts, so the four-post roster cannot be completed under the stated rules with the people available.
What he may do: escalate to the duty officer for a written decision; request a certified guard from another shift or from the reserve list; or, with authorisation, suspend the activity that requires the unstaffed post - for example, keeping the chest corridor locked and halting any cash movement through it - while the position is filled. E can be used only where no certification is required.
What he must not do: quietly park E at CC or CR because 'nothing usually happens', or leave a post empty without recording it. Both create an unrecorded breach that the next shift inherits.
The judgement being tested is that a shortage is a staffing problem, to be solved by escalation, not a compliance problem to be solved by wishful posting.
3. If only one rule could be relaxed to make the roster work, which should the supervisor refuse to relax, and why?
Read the worked answer
The chest-corridor training requirement is the one that must not be relaxed by the shift supervisor. The reasons are structural rather than personal. First, the CC post controls physical access to currency, so an untrained guard does not merely perform worse - he creates an uncontrolled access point, and the loss would be material and untraceable. Second, the requirement exists to satisfy audit and regulatory expectations; a verbal relaxation leaves no defensible record, so the supervisor personally absorbs the entire liability.
Fire certification for the Control Room is also a safety requirement and should not be traded away casually, but it is a life-safety competence that can sometimes be covered by temporary measures such as a certified relief guard or a reorganisation of posts. Chest access has no equivalent workaround.
A sound answer names the deciding principle: relax what can be restored later, never what cannot be undone. An untrained posting at the chest is not recoverable once access has occurred.