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The age of a father is 10 less than the sum of the ages of his two sons. 7 years ago his age was 3 times
the sum of the ages of his sons find their present ages
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f = s - 10, (1)
f-7 = 3*(s-14). (2) <<<<--- "14" must be distracted, not "7" !
---> (s-10) -7 = 3s - 42
s - 17 = 3s - 42,
2s = 42 - 17 = 25.
s = 12.5
Hello, the author!
1. Change the data in your problem to allow "s" to be integer.
2. From the given data it is impossible to determine the age of the two sons. Too few data.