Question

A partially dried clay mineral contains 8% water. The original sample contained 12% water and 45% silica. The % of silica in the partially dried sample is nearly:

• A. 50%
• B. 49%
• C. 55%
• D. 47%

Answer 1

The correct option is D 47%

Let us assume the sample as $100$ g

Original sample: 12 g of water and 45 g of silica.

Dried sample: 8 g of water and x 12 g of silica.

Total weight of the dried sample becomes $=96$ g now.

Percentage of silica in dried sample $=\frac{45}{96}\times 100=46.87\%$

Therefore, $47\%$ of silica is present in a partially dried sample.