The average of odd numbers upto 100 is:

50.5 50 49.5 51

50

Odd numbers up to 100 = 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, .........., 99. Sum =  1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 .................+ 99 Number of terms = \(\frac{first \; term \; + \; last \; term }{2}\) n = \(\frac{1+99}{2}\) = 50 The sum of odd numbers = n² = 50² = 2500 Average = \(\frac{50 × 50}{50}\) = 50