The sum of the weights of the five girls is 45 kg x 5 = <<45*5=225>>225 kg.
The sum of the weights of the five boys is 55 kg x 5 = <<55*5=275>>275 kg.
The sum of the weights of the ten students is 225 kg + 275 kg = <<225+275=500>>500 kg.
Hence, the average weight of those ten students is 500 kg/10 = <<500/10=50>>50 kg.
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