Who can solve this - Phil?

[Anti Marine Layer]

If you had two identical cups of 70 F water and added 5 identical ice cubes to each one, then put one cup outside in 80 F and the other cup in a refrigerator at 50 F, for which one would the average water temperature (excluding ice cubes) be colder after 5 minutes?

Obviously the ice would melt much faster in the first one. Over the long range the second one would get colder not only from the ice melting but the cooler air surrounding it. But the faster melting ice in the first one would probably cool it down faster at first.