Question 1125338
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Let M be the Mark's age.


Then the Chasity age is (M+64) years, according to the condition.


4 years ago:


    (M+64) - 4 = 3(M-4)


    M + 60 = 3M - 12


    72 = 3M - M

    72 = 2M  ====>  M = 72/2 = 36.


<U>Answer</U>.  Mark is 36 years now.
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Solved.