The two wires \( A \) and \( B \) of equal cross-section but of different materials are joined together. The ratio of Young's modulus of wire \( A \) and wire \( B \) is \( 20/11 \). When the joined wire is kept under certain tension the elongations in the wires \( A \) and \( B \) are equal. If the length of wire \( A \) is \( 2.2 \, \text{m} \), then the length of wire \( B \) is ______ \( \text{m} \).
