take npv with a grain of salt The combined wealth of the entire world in 2017 is $241 trillion.
King Tut lived in 1324 BC, 3341 years ago.
To determine interest for 3341 years at 7.5% interest, take 1.075 to the 3341 power.
1.075 to the 3341 power is 8 followed by 104 zeros.
$241 trillion is 241 followed by 12 zeros.
So, if King Tut had simply invested the tiniest sum of money, lets call it a half of a penny, the value of a single grape, at 7.5% interest, it would be worth far more than all the wealth in the world today.
Conversely, if someone promised to King Tut all the wealth in the world for Egypt in the year 2017 just for a grape in the year 1324 BC, King Tut's accountants would use NPV and say that it was worth far less than the value of a single grape - don't do it.