1) 4 + 1 4 + 2 4 + 4 3 + 4 1 = 2 1 4L.H.S = 4 + 1 4 + 2 4 + 4 3 + 4 1 = 1 2 6 ≠ R.H.S2) 5 + 1 5 + 2 5 + 5 3 + 5 1 = 2 1 5L.H.S = 5 + 1 5 2 5 + 5 3 + 5 1 = 1 4 9 ≠ R.H.S3) 6 + 1 6 + 2 6 + 6 3 + 6 1 = 2 1 6L.H.S = 6 + 1 6 + 2 6 + 6 3 + 6 1 = 1 7 2 ≠ R.H.S4) 8 + 1 8 + 2 8 + 8 3 + 8 1 = 2 1 8L.H.S = 8 + 1 8 + 2 8 + 8 3 + 8 1 = 2 1 8 = R.H.SHence, 8 is the correct answer.