Each conductor has a square cross section 3.00 mm on a side. The first material has a resistivity of 4.00 × 10⁻³ Ω · m and is 25.0 cm long, while the second material has a resistivity of 6.00 × 10⁻³ Ω · m and is 40.0 cm long. What is the resistance between the ends of the rod?