Calculating number of seed bags need for planting for a given number of acres

Question

Assuming that i have seed bag sizes of 1kg, 2 kg, and 5kg. And my clients typically have a land size between 0.25 and 5 acres and will plant 10kgs per acre.

What formualar can i use to calculate for each client the number of 5kg, 2kg and 1kg seed bags they need for planting. In the calculation, i want to try to assign the larger bags first while avoiding to assign half bags to a client as much as possible.

Shuri2060 · Accepted Answer · 2017-07-25T15:45:13.657

3

Let $m$ be the seeds in kilograms you need and $b_i$ be the number of bags of size $i$ kilograms needed.

Then

$b_5=\left\lfloor\frac{\lceil m\rceil}{5}\right\rfloor$

$b_2=\left\lfloor\frac{\lceil m\rceil-5b_5}{2}\right\rfloor$

$b_1=\lceil m\rceil-5b_5-2b_2$

Don't think there is a much nicer explicit formula.

There's always the option of calculating all the possibilities beforehand (there's only 50 of them and using a program is possible).

edited Jul 25 '17 at 15:45

answered Jul 25 '17 at 15:30

Shuri2060

4,353

$m$ must be rounded beforehand to the smallest higher integer. – Evargalo Jul 25 '17 at 15:31
@Evargalo I see your point - thanks! – Shuri2060 Jul 25 '17 at 15:33
It does make a difference. If I need 9.8kg of seeds, I prefer you giving me 2 bags of 5kg rather than four bags of 5,2,2 and 1. – Evargalo Jul 25 '17 at 15:33
Cross-posting. You're welcome ! – Evargalo Jul 25 '17 at 15:34

Calculating number of seed bags need for planting for a given number of acres

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