David is watching his dog, Buddy, run back and forth across the back yard. From the starting line ("0"), Buddy runs 6 1/2 yards to the right, then 5.75 yards to the left, then 8 1/2 yards to the right, and finally 9.25 yards to the left. Where does Buddy finish his run?

At the starting line

Step-by-step explanation:

Using the number line system, considering that his starting point is 0, let the movement to the left be negative and those to the right positive

Given that he moves  6 1/2 yards to the right, the equation of his movement will be

= + 6.5  (Considering that 6 1/2 is same as 6.5)

then 5.75 yards to the left, the equation becomes

= + 6.5 - 5.75

then 8 1/2 yards to the right, then the equation becomes

=  + 6.5 - 5.75  + 8.5 (again considering that 8 1/2 is same as 8.5)

and finally 9.25 yards to the left, the equation becomes

= + 6.5 - 5.75  + 8.5 - 9.25

simplifying

= 0

This means he finished his run at the starting line

$25 becasue a 10 increase would make it from 80 to 50

use a calculator or a graph