Question

The ratio of the masses of flour in two bags is 5:7. The heavier bag contains 1,120 grams of flour. What is the total mass of the flour in both bags?

Answer 1

`\bf \cfrac{light~bag}{heavy~bag}\qquad 5:7\qquad \cfrac{5}{7}\qquad \qquad \cfrac{b}{1120}=\cfrac{5}{7}\implies b=\cfrac{1120\cdot 5}{7}`

so the light bag is "b" grams of flour, so the total amount for both is 1120 + b.