Answer
Total mass of each amalgam=40 grams.
Mass of silver = 16.3 grams.
Work Step by Step
Total mass of each amalgam $=26.0 + 10.8 + 2.4 + 0.8 = 40.0 \,grams$
Mass of silver in 25 grams sample of amalgam = $\frac{25\times26}{40}=16.3 \,grams\,$