An aluminum rod is 10.0 cm long and a steel rod is 80.0 cm long when both rods are at a temperature of 15°C. Both rods have the same diameter. The rods are joined end-to-end to form a rod 60.0 cm long. The coefficients of linear expansion of aluminum and steel are 2.4 x 10-5 K-1, and 1.2 × 10-5 K-1, respectively. The temperature is raised to 90°C. The increase in the length of the joined rod, in mm, is closest to?