Answer:
Father=60
Son=20
Step-by-step explanation:
Let the father's age be x
Let the son age be y
Present age of them
X+y=80...(1)
Since the father's age equals to the present age of the son
Y+y=40
2y=40....(2)
Make y the subject of formula by dividing both sides by 2
Y=20
Substitute the value for x into (1)
20+x=80
Substrate 20 from both sides
X=60
Therefore the father's age is 60 and the son's age is 20