Current Electricity question bank (Physics)

A closed loop consists of a $15\ \text{V}$ battery, a $5\ \text{V}$ battery (opposing the first), and a $25\ \Omega$ resistor. The current through the loop is

An unknown resistance wire in the left gap of a meter bridge balances a $10\ \Omega$ resistance in the right gap at a point that divides the bridge wire in a ratio $3:2$. If the length of this unknown resistance wire is $1.5\ \text{m}$, what is its resistance per unit length? (Bridge wire is uniform)