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put this solution on YOUR website!"the sum of the present ages of Eric and his father is 58 years" __ e+f=58 __ f=58-e
"In 10 years his father will be twice as old as Ericwill be at that time" __ 2(e+10)=f+10
substituting __ 2e+20=58-e+10 __ 3e=48 __ e=16
substituting __ 16+f=58 __ f=42