Question 970067
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If the sum of their ages will be 28 in 5 years, the sum of their ages now is 
28 years-10 years=18 years  
T=Tim's age: S=Steve's age=T+4 yrs
T+S=18 yrs Substitute for S.
T+(T+4 yrs)=18 yrs Subtract 4 yrs from each side.
2T=14 yrs Divide each side by 2.
T=7yrs ANSWER 1: Tim is 7 years old.
S=T+4yrs=7yrs+4yrs=11 yrs ANSWER 2: Steve is 11 years old.
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CHECK:
(T+5yrs)+(S+5yrs)=28yrs
(7yrs+5Yrs)+(11yrs+5yrs)=28yrs
12yrs+16yrs=28yrs
28yrs=28yrs