Kevin's present age is 39 years
Daniel's present age is 3 years
Let's assume x be the required number of years
So, after x years
Kevin's age = 39+x
Daniel's age = 3+x
After x years it take until Kevin is only 4 times as old as Daniel
so,
we get
now, we can solve for x
Subtract both sides by 12
Subtract both sides by x
Divide both sides by 3
So, it will take 9 years...........Answer