<h2>
Answer:</h2>
P(rolling 1 or 5)=1/3
<h2>
Step-by-step explanation:</h2>
Let A represents the event of rolling a 1 on a number cube.
and B represents the event of rolling a 5 on a number cube.
Now we know that both the event A and B are independent.
Hence, we have:
P(A∩B)=0
Now, we are asked to find: P(A∪B)
P(A∪B)=P(A)+P(B)-P(A∩B)
Hence, we have:
P(A∪B)=P(A)+P(B)
P(A)=1/6
( Since the outcomes on a number cube are: {1,2,3,4,5,6} )
and
P(B)=1/6
P(A∪B)=1/6+1/6
i.e.
P(A∪B)=2/6
i.e.
P(A∪B)=1/3
Hence, the answer is: 1/3