How much of each popcorn size did you sell

Suppose the movie theater you work at sells popcorn in three different sizes. A small cost $2, a medium cost $5, and a large cost $10. On your shift, you sold 250 total containers of popcorn a brought in $1726. You sold twice as many large containers as the small ones.
How many of each popcorn size did you sell?
How much money did you bring in from selling small containers?
Please help me I've been working on this for 2 hours and 2 days now. So please help me solve this.
Oh, and show me how you got the answer too, so I understand it and will be able to answer other questions like that in the futures.
Thank you!

Suggestion:
1.Next time you're struggling with a word problem, write down all that you know.
2.Figure out what you need to know in terms of ONE variable.
3.Piece together an equation that will solve your variable.

small = $2
medium = $5
larger = $10
250 boxes sold
$1726 in sales
#small boxes sold = x
#large boxes sold = 2x
#medium boxes sold = 250 - (x + 2x) [The KEY piece to solving this puzzle!]

$2x +$10(2x) + $5(250 -3x) = $1726 [The rest is simple algebra]
2x +20x +1250 -15x = 1726 [put x's with x's, #s with #s]
2x +20x -15x = 1726 -1250
7x = 476
x = 476/7
x = 68

#small boxes sold = x = 68
#large boxes sold = 2x = 2(68) = 136
#medium boxes sold = 250 -3x = 250 - 3(68) = 46

Check:
$2(68) +$5(46) +$10(136)
= $136 +$230 +$1360 = $1726

No. Small Sizes = S
No. Medium Sizes = M
No. Large Sizes = L

S + M + L = 250 .............. Eq. 1

2S + 5M + 10L = 1726 .... Eq. 2

L = 2S ............................. Eq. 3


Sub 2S from Eq. 3 for L in Eq. 1:

S + M + 2S = 250
3S + M = 250
M = 250 - 3S .................. Eq. 4


Sub 2S for L in Eq. 2:

2S + 5M + 10(2S) = 1726
2S + 5M + 20S = 1726
22S + 5M = 1726 ............... Eq. 5


Sub 250 - 3S from Eq. 4 for M in Eq. 5:

22S + 5(250 - 3S) = 1726
22S + 1250 - 15S = 1726
7S = 1726 - 1250
7S = 476
S = 476 / 7
S = 68


Sub 68 for S in Eq. 4:

M = 250 - 3(68)
M = 250 - 204
M = 46

Sub 68 for S and 46 for M in Eq. 1:

68 + 46 + L = 250
114 + L = 250
L = 250 - 114
L = 136

No. Small Sizes = 68
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No. Medium Sizes = 46
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No. Large Sizes = 136
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Amt. Made from Small Sizes = 2(68) = $136
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S + M + L = 250
2S + 5M + 10L = 1726
2S = L

3 equations in 3 unknowns. Solve.