The average of nine consecutive numbers is n. If the next two numbers are also included the new average will increase by:

1

Note : In the case of consecutive numbers- The average increased = \(\frac{Total\;number\;more\;added}{2}\)

Therefore, average increased by = \(\frac{2}{2}\) = +1

OR

Avg. of nine consecutive no. = x

⸫ Fifth no. = x

10th no. = x + 5

11th no. = x + 6

New avg. =  \(\frac{9x\;+\;x+5\;+\;x+6}{11}\)

=  \(\frac{11x\;+\;11}{11}\)

= \(\frac{11(x\;+\;1)}{11}\)

= x + 1

Avg. increased by 1