You can put this solution on YOUR website! k = Karen's age now
d = Daniel's age now
:
Karen is 5 years older than the square age of Daniel's age.
k = d^2 + 5
:
In 20 years time, Karen's age will be double Daniel's age.
k + 20 = 2(d + 20)
:
k + 20 = 2d + 40
:
k = 2d + 40 - 20
:
k = 2d + 20
:
How old are they now?
:
Replace k with (d^2+5)
d^2 + 5 = 2d + 20
:
Arrange as a quadratic equation
d^2 - 2d + 5 - 20 = 0
:
d^2 - 2d - 15 = 0
:
Factors to:
(d-5)(d+3) = 0
:
Positive solution:
d = 5 yrs is Daniel's present age
then
5^2 + 5 = 30 yrs is Karen's age
:
:
Check solution in the statement
"In 20 years time Karen's age will be double Daniels age."
30 + 20 = 2(5 + 20)
