Is there a picture that goes with the question ?
In the figure below
1) Using the theorem of similar triangles (ΔBXY and ΔBAC),

Where

Thus,

thus, BC = 7.5
2) BX = 9, BA = 15, BY = 15, YC = y
In the above diagram,

Thus, from the theorem of similar triangles,

solving for y, we have

thus, YC = 10.
h=20w
in one week hector works 20 hours
in two hector works 40 etc
h = hours and w = weeks. the money is just extra information.
h=20w works because if it has been two weeks we substitute the w with the number 2 and can solve
h=20(2)
h=20x2
h=40
This proves that the equation is true
-4x - 17 ≥ -41
<u> +17 +17</u>
<u>-4x</u> ≥ <u>-24</u>
-4 -4
x ≥ 6