#### Answer

a) 0.333
b)0.5

#### Work Step by Step

a)We know that $probability=\frac{number \ of \ good \ outcomes}{number\ of\ all\ outcomes}$, hence $P(Identical \ twins)=\frac{5+0+0+5}{5+0+0+5+5+5+5+5}=0.333.$
b)We know that $probability=\frac{number \ of \ good \ outcomes}{number\ of\ all\ outcomes}$, hence $P(Identical \ twins| 2 \ Boys)=\frac{5}{5+5}=0.5.$