Question 343118
"Bob is one third of the age of his father" ___ B = (1/3)f


"In 12 years he will be half the age of his father" ___ B + 12 = (1/2)(f + 12)


substitute the equivalent value of B from the 1st equation into the 2nd equation and find "f"


then substitute the value of "f" into the first equation to find B