In following question, a number series is given with one term missing. Choose the correct alternative that will same pattern and fill in the blank spaces. - 563, 647, 479, 815,

Answer: D. 143

The pattern is + 84, - 168, + 336,.....  i.e. + 84, - (84 * 2), + (84 * 22),...
.'. Missing number = 815 - (84 * 22) = 815 - 672 = 143.