algebra
posted by Anonymous .
The Greek God Zeus ordered his blacksmith Hephaestus to create a perpetual watermaking machine to fill Zeus' mighty chalice. The volume of Zeus' chalice was reported to hold about one hundred and fifty sextillion gallons (that is a fifteen followed by twentytwo zeros). If Hephaetus' machine pours out 2 gallon in the first minute and then doubles its output each minute, find in which minute would this hypothetical machine pour out a single quantity of water that would be enough to fill Zeus' chalice with water?
1 hr, 2 min

1st. min2gal. = 2^1.
2nd. " 4gal. = 2^2.
3rd. " 8gal. = 2^3.
4th. " 16gal.= 2^4.
nth. min.15*10^22gal. = 2^x.
2^x = 15*10^22
x*Log2 = Log(15*10^22
x*Log2 = Log15+Log10^22
x*Log2 = Log15 + 22*Log10
x*Log2 = 1.17609 + 22
x*Log2 = 23.17609
Divide both sides by Log2:
X = 76.98931.
77th.min.15*10^22gal = 2^77.