Refer to the following number and symbol series and answer the question that follows. Counting is to be done from left to right only. (Left) < 7 5 9 @ ? 2 @ + 4 ? ? & 2 5 ? 1 % * (Right) How many such symbols are there, each of which is immediately preceded by a number and also immediately followed by a number?

Refer to the following letter, number, and symbol series and answer the question that follows. (NOTE: All numbers are single-digit numbers only.) (Left) H 2 @ Q I 3 L © £ R S 4 4 U © 9 1 W Y % 6 £ (Right) If all the symbols are dropped from the series, which element will be fifth from the left?

Which letter-number cluster will replace the question mark (?) in the given series to make it logically complete? AZA 27, XWX 36, UTU 45, RQR 54, ?