Take logarithm base d {\displaystyle d} of both sides: log d â¡ b c = log d â¡ a {\displaystyle \log _{d}b^{c}=\log _{d}a}. Simplify and solve for c {\displaystyle c} : c log d â¡ b = log d â¡ a {\displaystyle c\log _{d}b=\log _{d}a}. c = log d â¡ a log d â¡ b {\displaystyle c={\frac {\log _{d}a}{\log _{d}b}}}.
Price of a Stamp. The current price of a first class stamp is 49 cents. A domestic first class letter (1 oz.) is 49 cents. The price of each additional ounce is 21 cents. It will cost you 34 cents to send a domestic postcard. Postage Rate Timeline.
The current price for a forever stamp is .44 cents (2010) so 20 years from now the value of that same stamp will still be .44 cents, even if the price for one ounce is $2 then. So, you would need five forever stamps from this year for 1 ounce in 20 years.