4x + 2x = < y
This is because the opposite sides (which is 4x and 2x) of a triangle add up to the exterior angle (<y).
We have to find X.
As you know:

because the angles of a triangle add up to 180.
When we add them:


The 9 is multiplying with the X. We want X only and not 9 with it. So, when we take 9 to the other side, it becomes divide. As a result, the answer to x is:-

Substitute value of x into 4x and 2x to find the exterior angle:-
4x:

2x:

When we add them we get the answer for angle Y:-

Therefore, we can conclude that:

D because there are 10 gallons of gas remaining as you can see on the y axis and 10 gallons is being used for each 10 miles because 10 x 10 is 100 and the graph is counting up by 10
29 because the original answer would have been 28.26
A number considered in relative relation to a whole number.