Answer:
0.7
Step-by-step explanation:
Probability addition rule:
[tex]P(A\cup B)=P(A)+P(B)-P(A\cap B)[/tex]
In your case,
Event A = the soup of the day was ordered
Event B = the side salad was ordered
Event [tex]A\cap B[/tex] = the soup of the day and the side salad were ordered
Event [tex]A\cup B[/tex] = the soup of the day or the side salad were ordered
Hence,
[tex]P(A)=0.6\\ \\P(B)=0.4\\ \\P(A\cap B)=0.3[/tex]
and
[tex]P(A\cup B)=0.6+0.4-0.3=0.7[/tex]
