The average of nine consecutive numbers is n. If the next two numbers are also included the new average will increase by:
Answer & explanation
Correct answer: option 4
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