Give the step-by-step reasoning process and then the final answer. Ernest bought 50 meters of wire and cut it into 5 equal parts. He then used 3 parts of the wire. How many meters of wire is not used?
Each part of the wire is 50 / 5 = 10 meters long. Ernest used 3 parts, then he used 10 x 3 = 30 meters of the wire. Therefore, 50 - 30 = 20 meters of wire is not used.
The final answer: 20.