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 = <<50/5=10>>10 meters long.
Ernest used 3 parts, then he used 10 x 3 = <<3*10=30>>30 meters of the wire.
Therefore, 50 - 30 = <<50-30=20>>20 meters of wire is not used.
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