Mathematics
posted by Anonymous on .
"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.