I believe the answer you are looking for is 840 ÷ 17.5 which is 48 acres.
Answer: 0.2643
Step-by-step explanation:
Let p be the population proportion and
be the sample proportion .
As per given question , we have

z-score : 

The required probability ( using z-table ):-

Hence, the probability that the proportion of books checked out in a sample of 478 books would be less than 13% = 0.2643
It means for example instead of writing 2 2/5 You would write 12/5
You can find out an improper fraction by simply multiplying the denominator by the front number and adding the answer to you numerator
So, 2x5= 10. 10+2= 12. So 12/5