Formula to calculate next delivery

[Muddypaws]

Maths was never my forte at all, and I have just driven myself to the brink to work out how to formulate this calculation, and hope someone can help

The quandry is what will the next delivery date be, based on the following information

18kva Generator, on a qtr load, uses 24 litres a day (1ltr per hour), the fuel tank is 2000ltrs, and it runs 40hrs over a 5 day week (8hrs a day) the last delivery date was 1st February

100kva Generator, on a qtr load, uses 120 litres a day (5ltr per hour), the fuel tank is 2000 litres, and it runs 24/7, the last delivery date being 1st February


What will based on the above useage, the next delivery date be?

Thanks

 

[doofusboy]

For the first one, look at it this way [assuming no holidays]:
1 ltr/hour means it will use 40 ltrs every 7 days [8 hrs/day for 5 days = 40 plus 0 hrs on weekend]

So what you need to do is solve for 'X'.

40 ltrs is to 7 days as 2000 ltrs is to X days.

To solve for X, you would create the equation 40X = 7 times 2000. Or 40X = 14,000. Then X = 14,000 divided by 40. X = 350 days.

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Similarly for the other one:

5 ltrs / hour for 24 hours means 5 times 24 = 120 ltrs /day

120 is to 1 day as 2000 ltrs is to X days

120X = 2000

X = 2000 divided by 120, or 16.6666667 days