An alloy is made up of metals X and Y. Atoms of X are in ccp arrangement. Atoms of Y occupy half of the tetrahedral and all octahedral voids. Write the composition of the alloy.

Explanation

To determine the composition of the alloy made up of metals X and Y, we need to analyze the arrangement of the atoms and the voids in the cubic close-packed (ccp) structure.

### Step-by-Step Solution:

1. **Understanding the ccp Arrangement**:
- In a cubic close-packed (ccp) arrangement, the number of atoms per unit cell (denoted as Z) is 4. This means that in one unit cell of the ccp structure, there are 4 atoms of metal X.

2. **Calculating the Number of Tetrahedral and Octahedral Voids**:
...