16-(48- 16)÷(5- 1)

= 16-32÷4

= 16-8

=8 (year)

A: Eight years ago, my father was five times as old as Xiaogang.

problem analysis

From the meaning of the question, we can know that when the father's age was five times that of Xiaogang a few years ago, the age difference between the mother and Xiaogang was (5- 1) times that of Xiaogang, so we can get Xiaogang's age and subtract Xiaogang's current age.

The main characteristics of the age problem are: the age difference between the two is unchanged and does not change with the passage of time; The age of both will increase or decrease by the same natural number with the change of years; The multiple relationship of their age changes with the increase of age, and the multiple decreases with the increase of age.

According to the conditions of the topic, the age problem is transformed into "differential multiple problem", "sum difference problem" and "sum multiple problem" to solve.