A father’s age is 4 more than three times his son’s age. If the father is 61, find the son’s age.
Note
Let the son's age be x, because that is what the question asks for. Let the son's age be x. Then 3x+4=61, so x=19. The phrase '4 more than three times' means multiply by 3 first, then add 4. Solving the equation gives the son's age as 19.