question: There is one set of twins and one set of triplets. One twin is 7 years older than one triplet. If their combined ages are 44, how old is one of the twins?
answer: Let T = age of triplet
  Twin's age = T + <<+7=7>>7
  Twin's combined age = 2 * (T + 7)
  Triplet's combined age = <<3=3>>3T
  2 * (T + 7) + 3T = 44
  2T + 14 + 3T = 44
  5T + 14 = 44
  5T = 30
  T = <<6=6>>6
  Twin = 6 + 7 = <<6+7=13>>13
  The twins are each <<13=13>>13 years old.
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