At a picnic, a Styrofoam cup contains lemonade and ice at 0°C. The thickness of the cup is 4.0 10-3 m, and the area is 0.015 m2. The temperature at the outside surface of the cup is 28°C. The latent heat of fusion for ice is 3.35 105 J/kg. What mass of ice melts in 1.5 hours?