X would be less than 6 2/3.
The standard deviation is 1, I believe...
Answer: The total cost is
assuming the cost for 1 adult is
and the cost for 1 child is 
Step-by-step explanation:
Assuming the cost for 1 adult is
and the cost for 1 child is
:
and 
Then the expression that gives the total cost
is solved as:

Answer:
See method below.
Step-by-step explanation:
m/n + n/3 = 2
2/m + n = 4
First eliminate the fractions by multiplying the first equation by 3n:-
3m + n^2 = 6n...........(1)
and the second equation by m:-
2 + mn = 4m..............(2)
Now we solve using substitution:-
From equation (2):-
4m - mn = 2
m = 2 / (4 - n)
Now substitute for m in equation (1):-
6/ (4 - n) + n^2 = 6n
6 + n^2(4 - n) = 6n(4 - n)
6 + 4n^2 - n^3 = 24n - 6n^2
n^3 - 10n^2 + 24n - 6 = 0
This will not factor so we could solve this using graphical software.
To find the values of the variable m we substitute the found values of n into one of the original equations and solve for m.
Answer:
The temperature at the top of a mountain was -3°C in the afternoon. It fell down by 13°C at night. That will bring it to -16°