Tim and Pat were engaged by the local authorities to paint the lamp posts in a certain street. Tim, who was an early riser, arrived first on the job, and had painted three on the south side when Pat turned up and pointed out that Tim’s contract was for the north side.
So Tim started afresh on the north side and Pat continued on the south. When Pat had finished his side he went across the street and painted six posts for Tim, and then the job was finished.
There were an equal number of lamp-posts on each side of the street. Who painted more lamp posts, and how many more?
Pat must have painted six more lamp posts than Tim, no matter how many lamp posts there were.
Suppose there were 12 lamp posts on each side; then Pat painted 15 and Tim 9. If there were 100 lamp posts on each side, Pat painted 103, and Tim only 97.