Move a Safe

Puzzle Question:

To move a Safe, two cylindrical steel bars 7 inches in diameter are used as rollers.
How far will the safe have moved forward when the rollers have made one revolution?

Answer --

Solution of Puzzle:

The safe must have moved 22 inches forward.
If the rollers make one revolution, the safe will move the distance equal to the circumference of the roller. Hence, the distance covered by the safe is
= PI * Diameter (or 2 * PI * Radius)
= PI * 7
= 3.14159265 * 7
= 21.99115
= 22 inches approx

Toughness:

Intermediate