Question

Fertiliser is applied at the rate of a grams per square metre. It

takes b kilograms to cover a field of area c square metres. Find a
formula for b in terms of a and c.

Answer 1

Explanation:

1 kilogram (kg) = 1000 grams (g)

as "kilo" means 1000.

b = a × c / 1000

it is simple : we have "c" square meters. as we need to apply "a" grams per square meter, we need to multiply both numbers to know how many grams we need for that many square meters. hence a × c.

and to get kg, we need to divide this number of grams by 1000.

that's it.