Direction: Study the following sequence of letters, digits and symbols carefully:
$$8\cdot \text{F W }\$\text{ Y }56\text{G ? }71\text{E N \# P }3\text{@ J B }\Delta 4\text{M R }92+\text{ K}$$

How many symbols are there in the sequence that are immediately followed by a digit and preceded by a letter?

We need to look for patterns matching: **Letter $\to$ Symbol $\to$ Digit**.
Let's scan each symbol in the sequence:

1. $\cdot$ is preceded by $8$ (Digit) $\to$ Invalid.
2. \$isprecededby$ \text{W}$(Letter)andfollowedby$ \text{Y}$(Letter)$ \to$Invalid.3.$?$isprecededby$ \text{G}$(Letter)andfollowedby$ 7$(Digit)$ \to$\ast \ast Valid($ \text{G ? } 7$)\ast \ast 4.$ \#$isprecededby$ \text{N}$(Letter)andfollowedby$ \text{P}$(Letter)$ \to$Invalid.5.$ @$isprecededby$ 3$(Digit)$ \to$Invalid.6.$ \Delta$isprecededby$ \text{B}$(Letter)andfollowedby$ 4$(Digit)$ \to$\ast \ast Valid($ \text{B } \Delta\ 4$)\ast \ast 7.$ +$isprecededby$ 2$(Digit)$ \to$Invalid.Thereareexactly$ 2$suchsymbols($?$and$ \Delta$).