C. 155
Explain:
40 + 35 + 25 + 20 + 35 = 155
Since we aren't told the length of the 3rd bar, focus solely on the lengths of the first 2 bars. Add together their lengths: 1.15 cm + 3.92 cm = 5.07 cm.
Answer:
y = 5
Step-by-step explanation:
22.5(10-y)+27.5y=250

Combind like terms,

Subtract 225 from both equations to isolate the variable.

Divide both sides by 5 to isolate the variable and solve it.

Answer:


As we can see the z score for Ferdinad is higher than the z score for Emilia so on this case we can conclude that Ferdinand was better compared with his group of reference.
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Emilia case
Let X the random variable that represent the scores of a test, and we know that
Where
and
The z score formula is given by:
Since Emilia made 83 points we can find the z score like this:

Ferdinand case
Let X the random variable that represent the scores of a test, and we know that
Where
and
The z score formula is given by:
Since Ferdinand made 79 points we can find the z score like this:

As we can see the z score for Ferdinad is higher than the z score for Emilia so on this case we can conclude that Ferdinand was better compared with his group of reference.