Question 983923
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M=man's age; S=son's age
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M-S=27 years
M=S+27 years Use this to substitute for M below.
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M+S=68 years Substitute for M from above.
S+27yrs+S=68yrs
2S=41yrs
S=20.5 yrs
ANSWER: The son is 20.5 years old.
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CHECK:
M=S+27yrs=20.5yrs+27yrs=47.5yrs
The man is 47.5 years old.
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M+S=68 years
47.5yrs+20.5yrs=68 yrs
68yrs=68yrs