The scope of the problem

Hadley Bond, aged 22 months, was out for a walk with his mother. Although it was late autumn in the southern Australian city where they lived, the sun was still warm, and Hadley was becoming weary. His steps began to falter. Holly, his mother, checked her watch and found that they had been out for rather longer than she had intended. ‘My goodness, Hadley,’ she said, ‘guess how long we’ve been walking?’ ‘About twenty-six and a half minutes, I think,’ said Hadley – and he was right!