Answer
$0.15$
Work Step by Step
According to the first Rule for a Discrete Probability Distribution (see page 323):
$∑P(x)=1$
$P(0)+P(1)+P(2)+P(3)+P(4)+P(5)=1$
$0.30+0.15+P(2)+0.20+0.15+0.05=1$
$P(2)=1-0.30-0.15-0.20-0.15-0.05$
$P(2)=0.15$
Notice that: $0\leq P(2)\leq1$ (second Rule)
