5 consecutive integers : x, x + 1, x + 2, x + 3, x + 4
x + x + 1 + x + 2 + x + 3 + x + 4 = 505
5x + 10 = 505
5x = 505 - 10
5x = 495
x = 495/5
x = 99
x + 1 = 99 + 1 = 100
x + 2 = 99 + 2 = 101 <=== 3rd number is 101
x + 3 = 99 + 3 = 102
x + 4 = 99 + 4 = 103
