Question

Difficulty: HardRatios, Rates, and Proportions

A baker prepares a batch of sourdough bread using flour, water, and yeast. The correct recipe requires a flour-to-water ratio of 5:35:3 by weight, and a water-to-yeast ratio of 8:18:1 by weight. However, when mixing the ingredients, the baker accidentally uses a flour-to-water ratio of 3:23:2 by weight while keeping the correct water-to-yeast ratio of 8:18:1. If the baker used exactly 1212 ounces of yeast in this incorrect batch, how many ounces of flour must be added to the mixture to restore the correct flour-to-water ratio of 5:35:3?

  1. 1616Answer
  2. B
    3232
  3. C
    4848
  4. D
    9696
  5. E
    160160

Answer

The baker must add 1616 ounces of flour.
First, use the correct water-to-yeast ratio of 8:18:1 to find the weight of water in the batch. Since 1212 ounces of yeast were used, the weight of the water is 12×8=9612 \times 8 = 96 ounces. Next, determine the initial weight of flour using the incorrect flour-to-water ratio of 3:23:2. The initial weight of flour is 96×32=14496 \times \frac{3}{2} = 144 ounces. To restore the correct flour-to-water ratio of 5:35:3, find the target weight of flour for 9696 ounces of water, which is 96×53=16096 \times \frac{5}{3} = 160 ounces. Finally, subtract the initial weight of flour from the target weight of flour to find the additional flour needed: 160144=16160 - 144 = 16 ounces.

Step-by-Step Solution

1
Find the weight of water using the correct water-to-yeast ratio.
The water weight is 12 oz×8=96 ounces12 \text{ oz} \times 8 = 96 \text{ ounces}.
The water-to-yeast ratio is 8:18:1 by weight, and 1212 ounces of yeast were used.
2
Find the initial weight of flour in the incorrect batch.
The initial flour weight is 96 oz×32=144 ounces96 \text{ oz} \times \frac{3}{2} = 144 \text{ ounces}.
The incorrect batch was mixed with a flour-to-water ratio of 3:23:2 by weight.
3
Find the target weight of flour required for the correct ratio.
The target flour weight is 96 oz×53=160 ounces96 \text{ oz} \times \frac{5}{3} = 160 \text{ ounces}.
The correct recipe requires a flour-to-water ratio of 5:35:3 by weight.
4
Calculate the weight of additional flour needed.
The additional flour needed is 160 oz144 oz=16 ounces160 \text{ oz} - 144 \text{ oz} = 16 \text{ ounces}.
Subtracting the initial flour weight from the target flour weight gives the amount to be added.

Key Concept

Ratios and Proportions
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