SOLUTION: A dad is now three times as old as his son, but in eleven years the dad will be only two times as old as his son is then. How old will the dad be next year?

Algebra.Com
Question 316442: A dad is now three times as old as his son, but in eleven years the dad will be only two times as old as his son is then. How old will the dad be next year?
Answer by moshiz08(60)   (Show Source): You can put this solution on YOUR website!
Dad is three times as old as Son. Written as an equation this says (eq1)
In 11 years, Dad's age will be D+11. Son's age will be S+11. At that time, Dad will be only 2 times as old as Son, so . (eq2)
Let's plug in the expression for D given by (eq1) into (eq2).


Now distribute the 2 on the right hand side to get

Subtract 11 from both sides to get

Subtract 2S from both sides to get .
If the Son is 11, the Dad who is three times as old must be 33. Next year Dad will be 34.
Now we check. In 11 years, Son will be 22 and Dad will be 44. Indeed, Dad's age is two times the age of the son, so this answer checks.

RELATED QUESTIONS

Dad is three times as old as his son. In nine years dad will be twice as old as his son... (answered by fractalier)
Dad is 42 years old and his son is 10. In how many years will Dad be 3 times as old as... (answered by mananth)
dad is seven times as old as his son. 10 years later, he will be three times as old as... (answered by mananth)
Dad is seven times as old as his son. 10 years later, he will be three times as old as... (answered by jim_thompson5910)
Two years ago a father was four times as old as his son. Three years from now the father... (answered by ptaylor)
Two years ago a man was 7 times as old as his son, but in three years he will only be... (answered by richwmiller)
A man is 8 times as old as his son. In five years time he will be only four times as old. (answered by JBarnum)
a man is four timesaas old as his son. in 3 years, the father will be three times as old... (answered by mananth)
A mother is four times as old as his son. In 6 years, she will be three as old as he is.... (answered by macston)