Answer:
Emmas father would be 40 years old
Explanation:
if the father is 40 years old right now emma will be his age in 30 years.
in 30 years emma will be as old as he was when she was ten (10+30=40)
after the 30 years emmas father who was once 40 years when she asked how old he was would be 70 years old (30+40=70)