Study the arrangement and answer the question: 7 K M 3 P @ 9 B % T 4 W # 6 L $ 2. How many numbers in the arrangement are immediately preceded by a letter?

Checking each number's left neighbour: 7 (none), 3 (preceded by M, a letter), 9 (preceded by @), 4 (preceded by T, a letter), 6 (preceded by #), 2 (preceded by $). Only 3 and 4 are immediately preceded by a letter, giving two.