$P(A) = {5\over10} = {1\over 2}$
$P(B) = {2\over10} = {1\over5}$
$P(A)\cdot P(B) ={1\over 10}$
$P(A\cap B) = {1\over 10}$
Since $P(A)\cdot P(B) = P(A\cap B)$, the mathematical definition of independence is satisfied, so events $A$ and $B$ are independent