Question 104086
My average electricity bill for the months of November, December, January, and February was $200. The highest month was January which was twice February. December was $10 less than January and November was $24 less than February. How much was my bill in each of the months November, December, January, and February?
:
{{{(N + D + J + F)/4}}} = 200
:
Write equations for each statement:
:
"January which was twice February." 
J = 2F
or
F = .5J
:
"December was $10 less than January"
D = J - 10
:
"November was $24 less than February."
N = F - 24
We want to get everything in terms of J, substitute .5J for F:
N = .5J - 24
:
Substitute and you have;
{{{((.5J-24) + (J-10) + J + .5J)/4}}} = 200
:
Mult by 4 to get rid of the denominators, remove the brackets:
.5J - 24 + J - 10 + J + .5J = 800
:
.5J + J + J + .5J - 24 - 10 = 800; group like terms and do the math
3J - 34 = 800
3J = 800 + 34
J = 834/3
J = $278
Then
F = 278/2 = $139
and
N = 139 - 24 = $115
and
D = 278 - 10 = $268
:
:
Check on a calc:
{{{(115 + 268 + 278 + 139)/4}}} = 200