Answer
$\frac{3}{13}$
Work Step by Step
P(E) = $\frac{no.\ of\ outcomes\ in\ favor}{Total\ no\ of\ outcomes}$
There is a total of 52 cards, so there are 52 outcomes.
There are 12 cards that are greater than 3 but less than 7, so there is a total of 12 favorable outcomes.
P(E) = $\frac{12}{52}$ = $\frac{3}{13}$