Question

Potatoes with 85% moisture content on a wet basis are dried to a final moisture content of 10%. If we dry 100 kg of potatoes, what is the final weight of the product?

• A. 15.66 kg
• B. 16.66 kg
• C. 17.66 kg
• D. 18.66 kg

Hint:

For all drying and concentration problems, the key is to find the mass of the "bone-dry solids" first. This mass never changes. Then, use that solid mass to calculate the total weight at the new moisture content.

Answer 1

The Correct Option is B

Step 1: Identify the constant component. In a drying process, water is removed, but the mass of the solid material remains constant.

Step 2: Calculate the initial mass of solids.
Initial total weight = 100 kg
Initial moisture content = 85%
Initial solids content = 100% - 85% = 15%
Mass of solids = 100 kg 0.15 = 15 kg.

Step 3: Use the constant mass of solids to find the final total weight.
Final moisture content = 10%
Final solids content = 100% - 10% = 90%
The 15 kg of solids now constitutes 90% of the final product's weight. Final Weight 0.90 = 15 kg

Step 4: Solve for the Final Weight.
Final Weight = 15 kg / 0.90 = 16.666... kg.
Rounding to two decimal places gives 16.67 kg or 16.66 kg.