Let's first break it down to the time 8 people need for one wall. That would be 10 minutes, right? If one person would have to do it in stead of 8, you'd expect him to take 80 minutes.
To paint 7 walls, he would nee 7x80 = 560 minutes. 10 people would do that 10 times faster, ie., 56 minutes.
I know puzzles like these always have a mindtrick. Did I miss anything?? ;-)
The quadratic that has the roots x=8 and x=-5 is
x^2-3x-40
Hope this helps you! (:
-Hamilton1757
Answer:

Step-by-step explanation:
A is on the same point on the x-axis as B and the same point on the y-axis as D
- Therefore, the coordinate of A is (0,0)
C is on the same point on the x-axis as D and the same point on the y-axis as B.
- Therefore, the coordinate of C is (a,a)
We are to determine the slope of the line joining A to C.


Plug 50 into y and find x.
5x + 10 (50) = 800
5x + 500 = 800
5x = 800 - 500
5x = 300
x = 300 ÷ 5
x = 60