What will come next? 7 + 2 -1 = H, 22 + 6 -5 = W, 11 + 6 -2 = ?

What will come next? 7 + 2 -1 = H, 22 + 6 -5 = W, 11 + 6 -2 = ?

Explanation

 A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z.

7 + 2 -1 = H

9 - 1 = 8 

H is the 8th number in the alphabetical series

22 + 6 -5 = W

28 - 5 = 23

is the 23rd number in the alphabetical series

11 + 6 -2 = ?

17 - 2 = 15 

 O is the 15th number in the alphabetical series