She needs to know the distance from LA to SF.
Call that distance x. Then you can calculate the cost from:
# of gallons consumed: x miles / 38 miles/ gallon = (x/38) gallons
After that,
cost = # gallons * cost per gallon = (x/38) gallons * 4 $/gallon = 4x/38 $
I believe your answer is 23.
Credit: answers.yahoo.com
Hope this helps!
Answer:
P = 13.5 atm
Explanation:
Given that
No. of moles, n = 20 moles
Volume of nitrogen gas = 36.2 L
Temperature = 25°C = 298 K
We need to find the pressure of the gas. Using the ideal gas equation
PV = nRT
Where
R is gas constant, 
So,

so, the pressure of the gas is equal to 13.5 atm.