Answer:
15$
Step-by-step explanation:
I'm guessing theres only one friend based on the singular "friend" but if there was more please tell me
so we can do 5-20 = 15 and that 15 is what her friend had.
Answer:
80 screws
Step-by-step explanation:
25(4)-20
100-20
80
Answer:

Step-by-step explanation:
Hello there!
The first thing we want to do is find the measure of the large leg
To do so we use the Pythagorean theorem which says 
where a and b are legs and c is the hypotenuse
we want to find b given the hypotenuse and short leg
so 
all we have to do is plug in a ( a = short leg so a would equal 12) and c ( c = hypotenuse so c would equal 37)
so

so the longer leg is equal to 35
35=5x
divide each side by 5
5x/5=x
35/5=7
we're left with x=7
Answer:
And we can find this probability with thie difference:
And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.
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
Let X the random variable that represent the heights of a population, and for this case we know the distribution for X is given by:
Where
and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability with thie difference:
And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.