A kilogram of whole - wheat flour cost $6. what is the cost of 400 grams of the flour?

As you know, 1kq=1000g

To simplify the problem, we should get the amount of money 200g of flour will cost.

So we do 5/6 (5=amount of parts off 200g and 6=the amount of money) which equal to $1.2/200g

1.2*2=$2.4

Hence 400g=$2.4