Convoy Route and Water Resupply Decision
Your platoon is at Base A and must resupply Outpost C, 210 km away, before 1800. You have four trucks, each with a 60 L tank and a 10 L reserve. Route North is 240 km, mostly paved, averages 60 km/h, but includes a 30-minute checkpoint delay; consumption is 8 L per 100 km. Route South is 210 km, averages 45 km/h, has no delays, but consumption is 11 L per 100 km. The convoy must arrive within 6 hours of departure, and fuel at Outpost C is unavailable. For water, 24 cadets need 1.5 L per person per day for 3 days, plus a 20% reserve. The supply sergeant has 120 L of potable water loaded. Decide the route and whether the water load is sufficient, showing calculations.
1. Calculate travel time and fuel use for each route. Which route meets the 6-hour limit while preserving the 10 L reserve?
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Route North: time = 240 km ÷ 60 km/h = 4.0 h, plus 0.5 h checkpoint = 4.5 h. Fuel per truck = 2.4 × 8 = 19.2 L. Remaining fuel = 60 − 19.2 = 40.8 L, well above the 10 L reserve. Route South: time = 210 ÷ 45 = 4.667 h, or 4 h 40 min. Fuel per truck = 2.1 × 11 = 23.1 L. Remaining fuel = 60 − 23.1 = 36.9 L, also above reserve. Both routes meet the time limit, but North is faster and uses 3.9 L less fuel per truck. Choose North unless the checkpoint delay exceeds 2 hours, because 4.0 h driving + 2.0 h delay = 6.0 h exactly.
2. Compute the water requirement for 24 cadets for 3 days at 1.5 L per person per day plus a 20% reserve. Is the loaded 120 L sufficient?
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Baseline water = 24 × 1.5 × 3 = 108 L. Reserve = 20% of 108 = 21.6 L. Total requirement = 108 + 21.6 = 129.6 L. The loaded supply is 120 L, so the shortfall is 129.6 − 120 = 9.6 L, roughly 10 L. The load is not sufficient if the full reserve is to be maintained. The platoon must either draw 10 L more before departure, reduce the reserve to about 11%, or plan a resupply. Reducing daily consumption below 1.5 L per person is the least desirable option because it cuts into basic hydration.
3. If the North checkpoint delay becomes 90 minutes, does your route choice change? What delay would force a change?
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With a 90-minute delay, North time = 4.0 h + 1.5 h = 5.5 h, still under 6 h. Fuel is unchanged at 19.2 L per truck, so North remains feasible and still uses less fuel than South. The threshold is a delay of 2.0 h: at exactly 2 h, North reaches 6.0 h; beyond 2 h it fails the arrival limit. South remains about 4 h 40 min regardless, so if intelligence reports a delay above 2 h, switch to South despite the higher fuel burn. This is a judgement call: the route with the better margin is not automatically the one with lower fuel use once a time constraint binds.