Medium
Find the missing letter in the series: F7H, L13N, P17R, U22(?)
Explanation
Explanation
In each group, the last letter's alphabet position is 2 more than the first letter's position: F(6) and H(8); L(12) and N(14); P(16) and R(18). For U(21), the missing letter should be at position 23, which is W.
PRO TIP
Re-check your working by substituting the answer back into the original question.