The barometric pressure in inches of mercury at a height of h feet above sea level is
p=30.0e^-kh
where k=3.83*10^-5. At what height will the pressure be 10.0 in. of mercury.
I assume h is the height, so
30 e^(-kh) = 10
e^(-kh) = 1/3
- kh = ln (1/3)
-kh = -1.098612...
h = 1.098612/k = 28684.4
check:
30 ( e^(-.0000383(28684.4))
= 30(.3333333) = 9.9999997 , not bad