Parallel lines has equal slopes. Hence slope of line = -1/2
equation of line is (y - y1) = -1/2(x - x1)
y - (-6) = -1/2(x - 4)
y + 6 = -1/2x + 2
y = -1/2x + 2 - 6
y = -1/2x - 4
If you initially have 6 W, 4 R, and 8 B, and you take away two whites and a red, then you have 4W, 3 R and 8 B. There are 15 marbles total, and 8 black marbles, so you have an 8 in 15 or 53% chance of picking a black marble.
The next number is 38. The pattern is 7, 16, 8, 27, 9; if you look at the first 4 numbers, you notice that it counts to 7, 8, 9. Then you have 16 and 27, if the pattern continues; the next number is 38.
