The average of all the odd integers between 2 an 22…

Solution(By ExamCraze Team)

Series → 3 + 5 + 7 . . . . . 21
Total numbers
$$frac{{{text{Last term }} - {text{ First term}}}}{{{text{Difference}}}}$$     + 1
= $$frac{21 - 3}{2}$$ + 1
= $$frac{18}{2}$$ + 1
= 10
Sum of series
$$eqalign{ & = frac{n}{2}left[ {2a + left( {n - 1} right)d} right] cr & = frac{{10}}{2}left[ {2 times 3 + left( {10 - 1} right) times 2} right] cr & = 5left[ {6 + 9 times 2} right] cr & = 5 times 24 cr & = 120 cr} $$
Average = $$frac{120}{10}$$ = 12