Two identical coolers are packed for a camping. Each cooler is packed with ten-one liter softdrinks and 1.5 kg of ice. The softdrinks that were packed in cooler A were first put inside the refrigerator for 8 hours, while the softdrinks that were packed in cooler B were only kept at room temperature for 8 hours also. When the campers opened the coolers after 4 hours later, most of the ice in cooler A is still ice, while almost all of the ice in cooler B have already melted. Explain what happened with the two coolers.