Question

Four wires (all with different colors) need to be attached to a circuit board. A robotic device will

attach the wires. The wires can be attached in any order, and the production manager wishes to
determine which order would be fastest for the robot to use. Use the multiplication rule of counting
to determine the number of possible sequences of assembly that must be tested.

Answer 1

24

Explanation:

There are four options for the first wire.

After the first wire has been attached, there are three wires left that can be second.

After the second wire is attached, there are two wires that can be third.

After the third wire is attached, only one wire remains. It has to be last.

So the number of ways is:

4×3×2×1 = 24