Convoy Lift and Water Planning
Your cadet platoon of 84 officer cadets and 6 instructors must move from Camp Alpha to a training area 48 km away. Three trucks are available. Each truck has 24 seats, but unit policy reserves 4 seats per truck for stores and radios. Trucks travel in convoy at an average speed of 32 km/h, including a single 15-minute halt that must be taken after at least 30 minutes of driving. The training area gate closes at 08:30, and the first serial must arrive no later than 08:15. Water is carried at 20 litres per person per day; jerry cans hold 20 litres each; one day's water must be carried for all personnel. A truck can make one round trip in 3 hours 10 minutes including loading and unloading. The first serial departs at 06:00.
1. Calculate the usable seats per truck, the total number of personnel, and the number of loads needed.
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Usable seats per truck: 24 − 4 reserved = 20 seats. Total personnel: 84 cadets + 6 instructors = 90 personnel. Loads required: 90 ÷ 20 = 4.5, so 5 loads are needed. With three trucks, the first lift can carry 3 × 20 = 60 personnel; the second lift carries the remaining 30, using two trucks (40 seats available, 30 used). The arithmetic is simple, but the planning point is not: five loads with only three trucks means at least one truck must make a second trip, and the second lift cannot leave until the first trucks return and unload.
2. Calculate the total water requirement and the number of 20-litre jerry cans needed.
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Water per person per day = 20 litres. Total personnel = 90. Total water = 90 × 20 = 1,800 litres. Each jerry can holds 20 litres, so 1,800 ÷ 20 = 90 jerry cans. That is 30 cans per truck if evenly divided, which is a significant weight and space problem. A full 20-litre can weighs about 20 kg, so each truck would carry roughly 600 kg of water before personal kit. The candidate should flag this as a constraint, not just a number: the reserve seats for stores may not be enough, and the loading plan must confirm whether the cans can be secured without blocking exits. If the water is drawn at the training area instead, the calculation changes and the plan should say so.
3. Using the 06:00 departure, show whether the first serial arrives by 08:15, and assess whether all 90 personnel can arrive before the gate closes at 08:30.
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Travel time: 48 km ÷ 32 km/h = 1.5 hours = 90 minutes. Add the 15-minute halt: 90 + 15 = 105 minutes = 1 hour 45 minutes. Departure 06:00 + 1:45 = 07:45 arrival. That is 30 minutes before the 08:15 deadline, so the first serial is feasible, provided loading is complete by 06:00 and the halt is kept to 15 minutes.
The second lift is not feasible under the stated round-trip figure. If a truck returns in 3 hours 10 minutes including loading and unloading, the first trucks are not free until about 09:10. Even with optimistic unloading, a second departure cannot reach the gate before 08:30. Therefore all 90 personnel cannot arrive before the gate closes using this plan. The correct answer is not to squeeze more people into the trucks; it is to recommend a change: request an extended gate time, pre-position the second lift by another means, or reduce the first lift so that the second lift departs earlier with a returning truck. The candidate should state the shortfall plainly rather than report 'feasible' because the first serial works.