How much water is needed in the mixture used by a baker to prepare the

(1) 50 guests are expected to be present at the wedding. This tells us nothing about water or dough. Obviously insufficient.

(2) The amount of dough needed is 20 kilograms, and the dough is composed of water, flour, and yeast in the proportions 3:7:2 by weight, respectively. This says that water:flour:yeast = 3:7:2, and that we have 20 total kilograms of all ingredients. From this info alone, we know we could solve for the amount of water, so you should stop here and select B. But for completeness sake, let's solve for the water.

We know that, in the most basic ratios, we have 3 + 7 + 2 = 12 units of ingredients. To get 20 kilograms, we have to multiply this unit by some value to get 20.

12x = 20, x = \(\frac{20}{12}\), x = \(\frac{5}{3}\). Therefore, we multiply each piece of ingredient by \(\frac{5}{3}\) to get the amount needed for 20 kilograms.

water = 3 * \(\frac{5}{3}\) = 5 kilograms.
flour = 7 * \(\frac{5}{3}\) = \(\frac{35}{3}\) = 11.66 kilograms.
yeast = 2 * \(\frac{5}{3}\) = \(\frac{10}{3}\) = 3.33 kilograms.

Therefore, the amount of water needed is 5 kilograms.

Answer: B