Step-by-step explanation:
Will bought several books that cost $ 2.50 each and received a $ 2 discount on the total bill. If he paid $ 10.50, how many books did he buy ?
2.50x  - 2.00 = 10.50
2.50x = 10.50 + 2.00
2.50x = 12.50
x = 12.50/2.50
x = 5....he bought 5 books
 
        
                    
             
        
        
        
Answer:
What type of line the picture represent
 
        
             
        
        
        
Answer:
A sample of 499 is needed.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of  , and a confidence level of
, and a confidence level of  , we have the following confidence interval of proportions.
, we have the following confidence interval of proportions.

In which
z is the zscore that has a pvalue of  .
.
The margin of error is given by:

In this question, we have that:

90% confidence level
So  , z is the value of Z that has a pvalue of
, z is the value of Z that has a pvalue of  , so
, so  .
. 
How large a sample would be required in order to estimate the fraction of tenth graders reading at or below the eighth grade level at the 90% confidence level with an error of at most 0.03
We need a sample of n, which is found when  . So
. So






Rounding up
A sample of 499 is needed.
 
        
             
        
        
        
You forgot to put the decimal in there so i could round it 
        
                    
             
        
        
        
Unknown = x
the quotient of x and 12 is x/12 than 49 more than that is 53,
(x/12)+49=53, now use basic math and solve
-49 from both side,
x/12=4
*12 to both side,
x=48
therefore the unknown number is 48