Solution. LNG Transportation (#135)
Answer: 533.(3) tons
Solution
Since the ship’s capacity is 1,000 tons, we will call this amount of LNG a cargo. Initially, we have three full cargos. Clearly, we cannot transport all three cargoes entirely. To transport them for x miles, we will need 5x tons of LNG because we have to return twice. Let’s calculate how far we can deliver 2 cargos:
3000–5x = 2000
x = 200
The first FSU(Floating Storage Unit) shall be located at a distance of x miles from the plant. It was chosen this way because in the next move towards the terminal, we want to return fewer times. So, at this stage, we have 2,000 tons of LNG in the FSU located 200 miles from the plant. Let’s apply the same logic again.
To transport 2 cargos for y miles, we will need 3y tons of LNG because we have to return once. Let’s calculate how far we can deliver 1 cargo:
2000–3y = 1000
y = 333.(3)
In total, the second FSU is located at a distance of x + y miles from the plant and contains 1 full cargo. To transport it to the terminal, (1,000 — (x + y)) tons of LNG will be required. Therefore, the remaining amount on board is:
1000 — (1,000 — (x + y)) = x + y = 533.(3) tons
It’s exactly this amount that will be discharged at the terminal.
