A mathematician, a physicist and an engineer are each given $50
to measure the height of a building.
The mathematician buys a ruler and a sextant, and by determining
the angle subtended by the building a certain distance away from
the base, he establishes the height of the building.
The physicist buys a heavy ball and a stopwatch, climbs to the
top of the building and drops the ball. By measuring the time it
takes to hit the bottom, he establishes the height of the
building.
The engineer puts $40 into his pocket. By slipping the doorman
the other ten, he establishes the height of the building.