The alloy contains 14% tin. How many grams of alloy do you need to take to contain 98 grams of tin?

Let us find what is the ratio of the mass of tin to the mass of the alloy, which contains this tin.
Let’s denote the mass of the entire alloy through x.
From the condition of the problem it is known that the alloy contains 14% tin, therefore, the mass of tin included in this alloy is (14/100) * x = 0.14 * x.
Then the ratio of the mass of tin to the mass of the alloy, which includes this tin, is 0.14 * x / x = 0.14.
Therefore, in order for the alloy to contain 98 g of tin, the alloy must weigh 98 / 0.14 = 700 g.
Answer: you need to take 700 g of alloy.