Answer:
3 metres
Step-by-step explanation:
Let the width of the pathway be x
Area: (9+2x)(4+2x)
36 + 8x + 18x + 4x²
4x² + 26x + 36
Increased area is 150:
4x² + 26x + 36 = 150
4x² + 26x - 114 = 0
2x² + 13x - 57 = 0
2x² + 19x - 6x - 57 = 0
x(2x + 19) - 3(2x + 19) = 0
(x - 3)(2x + 19) = 0
x = 3, x = -19/2
Let n represent the amount Colin earned on Sunday.
On Sat. he earned n/2; on Sun. he earned n; and on Friday he earned (1/2)(n/2).
Then n/2 + n + n/4 = $70
Mult. all terms by 4 to eliminate fractions:
2n + 4n + n = $280
7n = $280 => n = $40
Colin earned n/2, or $20, on Saturday; n, or $40, on Sunday; and n/4, or $10, on Friday.
Note that $20 and $40 and $10 add up to $70, as they must.
We have the following function that is a
quadratic function:So the graph of this function is shown in the figure below. This is a <em>parabola</em> as you can see. The roots of this functions, that is, the x-intercepts are:
As you can see in the figure. This function decreases from
and increases from
Finally, another thing we can see from the graph is that the vertex is the point:
<span> x = 5/6 = 0.833.................</span>
The answer is 31
29 - 13 is 16
16 + 15 is 31