0.6%. 100% divided by 2,500 people means each person is worth 0.04%. 0.04 times 15 is 0.6
D + 3n = 1 Subtract d from both sides
3n = 1 - d Divide both sides by 3
n = 
You might want to stick to at most five questions at once, makes it easier for the rest of us. :)
17. T has a vertical line of symmetry (along the center line).
18. Z looks the same if you turn it halfway around.
19. The passes total to 150°, which is a little less than 180°, so I estimate it would be in front of Kai.
20. Left is the -x direction. Up is the +y direction. this is (x-6, y+4)
21. Every dilation has a center (where it's dilated from) and a scale factor (how much it's dilated).
22. It must be A, because it's the only one where the number of moves adds up to 16.
23. It can be determined to be B just by tracking where point C would end up through the transformation.
24. A 180° rotation flips the signs on both components to give you (-1, 6).
25. Right is the +x direction. Down is the -y direction. (x+3, y-5)
26. This is a reflection.
Need clarification on anything?
