Let:
A = Roll a 1
B = Roll a 2
m = Number of favourable outcomes
n = Total number of outcomes
So:
[tex]\begin{gathered} P(A)=\frac{m}{n}=\frac{1}{5} \\ P(B)=\frac{m}{n}=\frac{1}{5} \\ \end{gathered}[/tex]Since the events are mutually exclusive:
[tex]P(A\cup B)=P(A)+P(B)=\frac{1}{5}+\frac{1}{5}=\frac{2}{5}=0.400[/tex]Answer:
0.400
