I've been standing in line for a very long time to deserve to deliver this answer:
I think you already answered your own question:
Advanced math:
If Mark is 70 years old and his girldfriend is 26, how much #Bitcoin does Mark have? 
I've been standing in line for a very long time to deserve to deliver this answer:
I think you already answered your own question:
Advanced math:
If Mark is 70 years old and his girldfriend is 26, how much #Bitcoin does Mark have? 