A man was 27 years older than his son ten years ago.His wife is 4 years younger than he is.if their total age is 116 years now ,how old is the son?
m - 27 = s
w = m - 4
m + w + s = 116 ... substituting ... m + m - 4 + m - 27 = 116
solve for m , then substitute back to find s