400 / x = 100 / 3000 <=> 400 / x = 1 / 30 <=.> x = 400 * 30 <=> x = 12000 kilograms of grass.
To cover 3000 m², you will need 12 kilograms of grass seed, calculated from the rate of 400 grams per 100 m². This equals 4 grams per square meter, resulting in a total of 12000 grams or 12 kilograms. Hence, the total amount of seed required is 12 kg.
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