65 % ------------------ 23.4 items
100 % ----------------- x items
65 : 100 = 23.4 : x
65 x = 100 * 23.4
65 x = 2340
x = 2340 : 65
x = 36
Answer: there were 36 items on the test.
2 cubic yards turns into 52 cubic feet.
Hope this helps.
Another way to solve this is to use the Midpoint Formula. The midpoint of a segment joining points

and

is

So the midpoint of your segment is

Perhaps it helps to see that the x-coordinate of the midpoint is just the average of the x-coordinates of the points. Ditto for the y-coordinate of the midpoint; just average the y's.
b since it is equal and graeter than -7