Question

A sample of clay was partially dried and then found to contain 60% silica and 8% water .The original sample of clay contained 15% water. Find the percentage of silica in the original sample.

(a) 52.3% 

(b) 47.8% 

(c) 55.5% 

(d) 51.7%

Answer 1

Correct option: (c) 55.5%

Explanation:

Let suppose mass of original sample = 100 gm

mass of water in original sample = 15 gm.

and mass of (impurity + silica) in original sample = 85 gm.

% water after drying = 8%.

Let x be the mass of water left and y be the mass of silica in original sample.