The atmospheric pressure P in pounds per square inch (psi) is given by

P = 14.7 e^−0.21 a
where a is the altitude above sea level (in miles). If a city has an atmospheric pressure of 11.35 psi, what is its altitude?

3 answers

Thought this looked familar.

Just change the numbers a bit

http://www.jiskha.com/display.cgi?id=1384227123
answer is 6503 miles?
I have no clue how you got your answer, but did you think about the validity of your answer?

A city 6503 miles high would put it in a pretty high orbit.
The space station is only about 230 miles high.

11.35 = 14.7 e^(-.21a)
.7721088.. = e^(-.21a)
-.21a ln e = ln .7721088..
a = ln .7721088.. / -.21 , remember ln e = 1

=1.2315 miles or appr 6500 ft