5. (10 points) This year, Feifei's age is 12 years more than half of Leilei's age; next year, Feifei's age will be 34 years less than twice Leilei's age. The sum of their ages this year is $\qquad$ years.
【Answer】Solution: Let half of Lili's age this year be 1 unit, then Feifei's age is 1 unit + 12 years, next year Lili's age doubled is 4 units + 2 years, Feifei's age is 1 unit + 13 years, 3 units is $34+13-2=45$ years, 1 unit is $45 \div 3=15$ years, so, Lili's age this year is $15 \times 2=30$ years, Feifei's age is 27 years, so the sum of their ages this year is 57 years, hence the answer is 57.