By finding a linear equation, we conclude that the length of 21 carts is 153 in
Here we know that:
Now, the relation between the length L and the number of carts x must be a linear relation:
L = a*x + b
Where a is the slope and b is the y-intercept.
Here we have 2 points (4, 51in) and (5, 57 in), then the slope is:
a = (57 in - 51 in)/(5 - 4) = 6in
Then the line is something like:
L = 6in*x + b
To find the value of b, we use one of the given points, like (4, 51 in), it means that when x = 4, we must have L = 51in.
51in = 6in*4 + b
51in = 24in + b
51in - 24 in = b = 27in
Then the linear equation is:
L = 6in*x + 27in
The length for a total of 21 carts is what we get when we evaluate in x = 21, so we will get:
L = 6in*21 + 27in = 153 in
If you want to learn more about linear equations:
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