Description for Correct answer:
Let the first natural number be x

According to the question

x+x+1x+2+x+3+x+4+x+5+x+6+x+7+x+8+x+9+x+10=2761

=> 11x + 55 = 2761

x = \( \Large \frac{2761 - 55}{11} = 246 \)

Middle number = x + 5 = 246 + 5 = 251