[yellow]

$n(E) = \binom{3}{1} \binom{7}{1} \binom{20}{1} + \binom{7}{1} \binom{20}{2} = 1,750$

$n(S) = \binom{30}{3} = 4,060$

$P(E) = \frac{1,750}{4,060} = \frac{25}{58} $