Answer: He should order for 1046.67 litres fuel to be certain that he has enough for the next two weeks
Explanation:
Note that he has just completely
filled the fuel tank of the lorry with 170 litres from empty. He now has 100 litres of fuel left in his storage tank
If his regular short daily trips total 300 km and this leaves just 20 litres in the lorry's fuel tank.
That is 100 litres -20 litres = 80 litres
On 300km, he consumed 80 litres
He plans to complete three regular days of 300 km journeys each week, but this could rise to five. Sometimes the total journeys are longer but his daily trips never total more than 400 km in a day. He never works more than five days in a week. His storage container holds
4000 litres
From all these analysis, we can deduce that the maximum km of journey he should prepare for is
400km × 5 = 2000km for one week
Since he consumed 80 litres of fuel for any 300km
Then,
80/300 = L/2000
L = 1600/3
L = 533.33 litres
The journey for two weeks will be
533.33 × 2 = 1066.67 litres
Recall that he left 20 litres in the tank. Take this away from 1066.67 litres.
1066.67 - 20 = 1046.67 litres
He should therefore order for 1046.67 litres fuel to be certain that he has enough for the next two weeks