How old is my dad?

How old is my dad?

My uncle Dan is 18 years younger than my dad. Both digits in my dad’s age are prime numbers and, when switched, are my uncle Dan’s age. If Uncle Dan is not yet 40, how old is Dad?

53

53

53

way too old!

53

2 months ago

53

53

53

75

31

53 years

40

31

53

35