Question

Drinking 6 fluid ounces of milk provides 202.5 milligrams of calcium. how many fluid ounces of milk provide 85.5 milligrams of calcium

Answer 1

6 / 202.5 = x / 85.5.....6 oz to 202.5 mg = x oz to 85.5 mg
cross multiply because this is a proportion
(202.5)(x) = (6)(85.5)
202.5x = 513
x = 513 / 202.5
x = 2.53 oz <==

Answer 2

$\frac{85.5}{202.5} \times 6 = 2.53\ ounces\ of\ milk$