A traveling salesman, whose feet often ached from excessive walking, was advised by his doctor that salt water was the best remedy. He decided to spend his vacation by the sea. However, as hotels near the beach were expensive, he chose a small hotel farther inland.
In the morning, he went to the calm sea with a bucket. He approached the lifeguard and asked if he could take a bucket of salt water. The lifeguard, looking surprised, agreed but charged twenty-five cents. The salesman paid, filled his bucket, took it to his hotel, and soaked his feet.
After lunch, he returned to the beach. The tide had gone out, and the sea was much lower. Seeing this, the salesman thought, "That man runs a good business. He must have sold thousands of buckets since this morning."