Answer:
a. Please refer to the diagram below
b. 0.385875
Step-by-step explanation:
The tree diagram is shown below.
To calculate the probability of at least one sale to the three customers, we have to ways. The easier way is to calculate the probability of no sales to three and subtract the value from one:
[tex]1-0.614125=0.385875[/tex]
Other way is to calculate the sum of following probabilities:
One sale + Two sale + Three sale.
[tex]0.003375+0.019125+0.019125+0.108375+0.019125+0.108375+0.108375=0.385875[/tex]
For the probability, please refer to the tree diagram. If moving to the sub branch of the previous branch, we multiply the probability; otherwise we add.