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191. Billy and Tommy, two aboriginals, killed a kangaroo in the bush,
and began quarrelling over the weight of the animal. They had no
proper means of weighing it, but, knowing their own weights, Billy
130 lbs. and Tommy 190 lbs., they placed a log of wood across a stump
so that it balanced with one on each end. They then exchanged places,
and, the lighter man taking the kangaroo on his knees, the log again
balanced. What was the weight of the kangaroo?
192. A son asked his father how old he was, and received the
following answer: “Your age is now one quarter of mine, but five
years ago it was only one-fifth.” How old is the father?