In the series W 3 K $ B 8 N T 5 ? R 2 * 9 G 6 # V, how many symbols have a letter standing immediately on one side of them and a digit standing immediately on the other?

The four symbols are $, ?, * and #. $ has K on its left and B on its right — two letters, so it fails. ? has the digit 5 on its left and the letter R on its right — it qualifies. * has 2 on its left and 9 on its right — two digits, so it fails. # has the digit 6 on its left and the letter V on its right — it qualifies. That makes 2. Answering 3 or 4 comes of letting $ or * through on a single neighbour, and 1 of stopping at the first symbol found.