Question 1195826
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Tommy is three years older than Jack. Sadie is seven less than twice Jack’s age. 
Sadie and Tommy are twins. How old is jack
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Write equations as you read the problem

    T = J + 3,      (1)

    S = 2J - 7,     (2)

    S = J.          (3)


Equation (3) implies

    J + 3 = 2J - 7,

or

    3 + 7 = 2J - J

      10  =    J


<U>ANSWER</U>.  Jack is 10 years old.
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Solved.