Consider the series: 5 G T 2 % 7 J K 9 B & M 4 R 8 D. Read from the left, its letters are G, T, J, K, B, M, R, D. Which letter of the English alphabet lies exactly midway between the third and the seventh of these eight letters?

The third of the eight letters is J and the seventh is R. J is the 10th letter of the alphabet and R the 18th, so the midpoint is (10 + 18) ÷ 2 = 14, which is N. Counting on from J, the letters K, L, M lead to N and the letters O, P, Q lead to R — three on either side, as a midpoint requires. M and O are the one-place slips to either side, and P is where you finish if you take the third and seventh letters as K and S instead.