Answer:- 0.88
Solution:- Masses of silver and copper metals are given and we are asked to calculate the percentage of silver in the alloy.
mass percent of Ag =

Mass of Ag = 17.6 g
mass of Cu = 2.40 g
mass of alloy = 17.6 g + 2.40 g = 20.0 g
Let's plug in the values in the formula:
mass percentage of Ag =

mass percentage of Ag = 88%
So, the mass percentage of silver in sterling silver is 88% and in decimal form it is 0.88.