Answer:
Mean=50.
standard deviation=50.
Step-by-step explanation:
Let the perfect score be 100.
The mean(average) of a data is given by: 
Here the number of data points are 100. out of which 50 attains a value 100,and 50 attains value 0.
so, sum of data points=50×100+50×0=5000.
Mean=50.
"Now the standard deviation of data points are calculated by firstly subtracting mean from every entry and then square the number and take it as new entry and calculate the mean of the new data entry and lastly taking the square root of this new mean".
Here if 50 is subtracted from each entry the new entry will have 50 entries as '50' and 50 entries as '-50'.
next on squaring we will have all the 100 entries as '2500'.
now the mean of these entries is: 
=2500
taking it's squareroot we have 
Hence, standard deviation=50.
Answer:
x−3=x−3
Step-by-step explanation:
Evaluate (2x−1)−7, then set it equal to 2.
Subtract 7 from −1 = 2x−8
Solve 2x−8=2.
Move all terms not containing x to the right side of the equation.
Add 8 to both sides of the equation=2x=2+8
Add 2 and 8=2x=10
Divide each term by 2 and simplify.
Divide each term in 2x=10 by 2=2x/2=10/2
Cancel the common factor of 2
Cancel the common factor=10/2
Divide x by 1=x=10/2
Divide 10 by 2=x=5
Remove parentheses=x−3
List all of the solutions.
5=
(2x−1)−7=2=x=5
x−3=x−3
10lb. of jam needs 5lb. apple, or 2lb. of jam needs 1lb. apple.
Now we want 8lb. of jam.
Set up a proportion:
2/1=8/x
Solve for x by cross-multiplying.
2x=8
x=4 lb. of apple
Answer:
60.32 cm²
Step-by-step explanation:
<span>add 13.3 + (–7)
= 13.3 - 7 = 6.3
</span>Subtract.
<span>–56 – (–27.07)
</span>= -56 + <span>27.07
= -28.93
</span>simplify
<span>14- (-8)+5 -(-10)
</span>= 14 + 8 + 5 + 10
= 37
