Question 1167305
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Let x = Josef's age.


Then his father's age is 7x, according to the condition.


One year ago

    7x - 1 = 9*(x-1)


Simplify and solve

    7x - 1 = 9x - 9

    9 - 1 = 9x - 7x

      8   = 2x

      x   = 8/2 = 4.


<U>ANSWER</U>.  Josef is 4 years old now.
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Solved.