"Kim is 15. Kim's father is 39. In how many years will Kim's father be exactly twice as old as Kim will be?"
let the number of years be x
x+39 = 2(15+x)
x+39 = 30 + 2x
9 = x
check:
in 9 yrs from now, kim will be 24 and Kim's dad will be 48 , which is twice Kim's age.
To find the number of years, let's denote the unknown number of years as "x."
Currently, Kim is 15 years old, and their father is 39 years old. After x years, Kim's age will be 15 + x, and their father's age will be 39 + x.
According to the problem statement, we are looking for the point in time when Kim's father will be exactly twice as old as Kim will be. Mathematically, it can be expressed as:
39 + x = 2(15 + x)
Now we can solve for x to get the number of years:
39 + x = 30 + 2x
x - 2x = 30 - 39
-x = -9
x = 9
Therefore, in 9 years, Kim's father will be exactly twice as old as Kim will be.