
What would be the next colour in the sequence.
The correct answer will also state the logic behind it.
This is the next image in the sequence:

Look at the hex colours for each image - each pair increments on a different scale.
Pair 1: 3C 4E 60 72 ... 84 (+18)
Pair 2: 55 5C 63 6A ... 71 (+7)
Pair 3: 64 66 68 6A ... 6C (+2)
The increments have been chosen because
Letter 18 is R, letter 7 is G and letter 2 is B - RGB is the ugly twin sister of HEX colors (ugly twin sister in CSS, anyway :P)
For giggles, you could also argue that there's a 4th pair:
Pair 4: 1, 1, 1 ... 1 (RGBA is RGB with Alpha, ie. opacity)