F should be -1, 6
E should be -4, 2
D should be -4, 9
Answer:
Jaw saw an average of 6 birds each day
Step-by-step explanation:
Given: One day, Jean saw 7 birds. The next day, she saw 11 birds. The next day, she saw no birds.
To find: average number of birds Jean saw each day
Solution:
Average is a central value of a set of terms.
Average of terms is given by
Number of birds, Jean saw on day one = 7
Number of birds, Jean saw on the second one = 7
Number of birds, Jean saw on the third one = 7
So,
average number of birds Jean saw each day =
Therefore,
Jaw saw an average of 6 birds each day
We are going to make simultaneous equations.
x will be our $3 ice cream and y will be our $5 ice cream
Equation1 ---- x + y = 50 (the sum of all the ice creams they sell)
Equation 2 ---- 3x + 5y = 180 Sum of all the $3 and $5 ice creams is $180
Since we can't solve for both variables we will put one of the variables in terms of the other.
Take x+y=50 and subtract y from both sides. (I could have done subtracted x - it did not matter). Now we have x= ₋ y +50 (negative y +50)
Now I am going to take equation 2 and replace the x with -y +50
3 (-y +50) + 5y = 180
Now I will use the distributive law on the 3 and what's in the parentheses:
-3y + 150 + 5y = 180
Now I will combine like terms (the -3y and the 5y)
2y + 150 = 180
Now subtract 150 from both sides of the equation
2y = 30
Divide both sides by 2
and get y= 15 They sold 15 ice creams that cost $5 each
Since equation 1 is x+y=50 we can replace y with 15
x + 15 = 50 Now subtract 15 from both sides x = 35
Since x represents the $3 ice creams, they sold 35 of those.
Check:
35 X 3 = $105
15 x 5 = + <u>75
</u> $180
Answer: -8 and -4
This is something you do through trial and error. Making a list or a table like shown below might help.
Answer: 0.935
Explanation:
Let S = z-score that has a probability of 0.175 to the right.
In terms of normal distribution, the expression "probability to the right" means the probability of having a z-score of more than a particular z-score, which is Z in our definition of variable Z. In terms of equation:
P(z ≥ S) = 0.175 (1)
Equation (1) is solvable using a normal distribution calculator (like the online calculator in this link: http://stattrek.com/online-calculator/normal.aspx). However, the calculator of this type most likely provides the value of P(z ≤ Z), the probability to the left of S.
Nevertheless, we can use the following equation:
P(z ≤ S) + P(z ≥ S) = 1
⇔ P(z ≤ S) = 1 - P(z ≥ S) (2)
Now using equations (1) and (2):
P(z ≤ S) = 1 - P(z ≥ S)
P(z ≤ S) = 1 - 0.175
P(z ≤ S) = 0.825
Using a normal distribution calculator (like in this link: http://stattrek.com/online-calculator/normal.aspx),
P(z ≤ S) = 0.825
⇔ S = 0.935
Hence, the z-score of 0.935 has a probability 0.175 to the right.