Answer:
-51
Step-by-step explanation:
PEMDAS suggests you start with parenthesis
10+9•(-3)2-(7)
10-(27)2-(7)
10-54-7
-51
Answer:
1.165.
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
So it is z with a pvalue of 
, so 
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
In this problem, we have that:
. So
So the correct answer is:
1.165.
Answer:
b
Step-by-step explanation:
i took the test
9514 1404 393
Answer:
- 100 mL of 75% solution
- 150 mL of pure alcohol
Step-by-step explanation:
Let x represent the quantity (in mL) of pure alcohol needed for the mix. Then the amount of 75% needed is (250-x). The amount of alcohol in the mixture is ...
1.00x +0.75(250 -x) = 0.90(250)
0.25x +187.5 = 225 . . simplify
0.25x = 37.5 . . . . . . . . subtract 187.5
x = 150 . . . . . . . . . . . . . divide by 0.25
(250 -x) = 100 . . . . mL of 75% solution
You need 100 mL of the 75% solution and 150 mL of pure alcohol to obtain the desired mixture.
