Four friends are waiting in line. how many different ways can they arrange themselves in that line?
2 answers:
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Answer:
The dimensions of the yard are W=20ft and L=40ft.
Step-by-step explanation:
Let be:
W: width of the yard.
L:length.
Now, we can write the equation of that relates length and width:
(Equation #1)
The area of the yard can be expressed as (using equation #1 into #2):
(Equation #2)
Since the Area of the yard is , then equation #2 turns into:
Now, we rearrange this equation:
We can divide the equation by 5 :
We need to find the solution for this quadratic. Let's find the factors of 160 that multiplied yields -160 and added yields -12. Let's choose -20 and 8, since and
. The equation factorised looks like this:
Therefore the possible solutions are W=20 and W=-8. We discard W=-8 since width must be a positive number. To find the length, we substitute the value of W in equation #1:
Therefore, the dimensions of the yard are W=20ft and L=40ft.