Out put per day is 50 tonnes(40x103 kg) per day, nutrient is 15ppm, total nutrient = 0.75kg
The large mixer can do 3 tonnes at a time.
This is not usefully divisive, giving 17 mixes of 2.94 tonnes
Therefore preferable to use 20 mixes, each of 2.5 tonnes. This decision depends on the time of mixing and the total time in the day, and also the cost of 3 extra mixes. But difficult to weigh 2.94 tonnes.
The mix contains 15ppm, therefore each 2.5 tonnes (2,500 kg) must contain 15/106 x 2500
= 0.0375kg nutrient
It would be preferable if the second mixer were also doing 20 mixes per day.
The second mixer can mix 0.5 tonnes, maximum 20 x 0.5 = 10 tonnes
Each mix would need to contain 0.0375kg nutrient i.e. 0.0375kg in 500kg
First mixer, 0.05 tonnes = 50kg , minimum 8.3kg.
0.0375kg in 50kg i.e. 37.5 g per mix which is easy to weigh.
Start with 37.5 g in 50kg, with 20 batches, total nutrient is 0.75kg
In second mixer, 50kg mixed with 450kg, i.e. 500kg per mix
In third mixer 0.5 tonnes (500kg) mixed with 2 tonnes (2,000kg) of other material, giving 2.5 tonnes.