12 because the rest of the numbers are all similar except 12
I think it's 65 no reasoning
Go and study circle thermos
Answer:
50 percent
Step-by-step explanation:
Mean = 39

Using the 68-95-99.7 rule, 68% of the data falls within first standard deviation of mean

95% data falls within two standard deviation of mean

99.7% data falls within 3 standard deviation of mean

Refer the attached graph
The curve is normally distributed
Now the the percentage of light bulb replacement requests numbering between 39 and 48 = 34%+13.5%+2.5% = 50%
Hence the approximate percentage of light bulb replacement requests numbering between 39 and 48 is 50 .