If a, b, c, d, e & f are six consecutive odd numbers, their average is :

(a + 5)

Let the numbers a,b,c,d,e are = 3 , 5 , 7 , 9 , 11 , 13

Average = \(\frac{Sum \; of \; numbers}{Total \; number \; of \; numbers}\)

              =  \(\frac{ 3 + 5 + 7 + 9 + 11 + 13}{6}\) = 8

Now verify from options = Choose option (a + 5)

Here a = 3

a + 5 = 3 + 5 = 8 verified

Ans. = (a + 5)