<h3>
Answer: 0.6 grams per cm</h3>
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Explanation:
Pick any column and divide the weight over the length
column 1: 9/15 = 0.6
column 2: 12/20 = 0.6
column 3: 18/30 = 0.6
column 4: 30/50 = 0.6
The weight per cm is 0.6 grams per cm
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Another way you could look at is like so
9 g = 15 cm
9/15 g = 15/15 cm
0.6 g = 1 cm
We divided both sides by 15 to turn "15 cm" into "1 cm". Think of "per cm" as "per 1 cm". This works for any other column as well.
We've got the first number, so now we need the others.
There is 1 possibilty for the first digit, 10 for the middle ones, and 2 for the last one.
1*10*10*2=200
200 possible codes for this briefcase
4x(y-1)+3(y-1)---(y-1)(4x+3)
the answer is the first one
X-(4x-7)=5x-(x+21)
x-4x+7=5x-x-21
-3x+7=4x-21
-7 -7
-3x=4x-28
-4x -4x
-7x=-28
/-7 /-7
x=4
