The Poisson's ratio of a material is 0.1. If the longitudinal strain of a rod of this material is $$10^{-3}$$, then the percentage change in the volume of the rod will be

A steel wire of length 4.7 m and cross-sectional area $$3.0\times10^{-5}$$ m$$^2$$ stretches by the same amount as a copper wire of length 3.5 m and cross-sectional area of $$4.0\times10^{-5}~\mathrm{m^2}$$ under a given load. What is the ratio of Young's modulus of steel to that of copper?