Answer:
7 trays
Step-by-step explanation:
Given the [tex]\mu=5, \sigma=1[/tex], the z score is obtained using the formula:
[tex]z=\frac{x-\mu}{\sigma}[/tex]
The z score value for a 95% interval is 1.645.
#Substitute our z value and solve for x:
[tex]z=\frac{x-\mu}{\sigma}\\\\1.645=\frac{x-5}{1}\\\\1.645+5=x\\\\x=6.645\approx7[/tex]
Hence, the bakery must prepare 7 trays of doughnuts .