Weight and how to do simple math

Question

If 28 grams is worth $350 how many grams would be worth $100?

Answer 1

(350 / 28) = (100 / x)

Now, you can cross-multiply and solve for x:

350x = 28 * 100

350x = 2800

x = 2800 / 350

x = 8

So, 8 grams would be worth $100 based on the given ratio.