Answer:
For this exercise we need to solve the next equation:
3 +6x = 2x + 27
We can start substracting 3 at both sides:
3 + 6x - 2 = 2x + 27 - 3
6x = 2x + 25
And then, we can substract 2x::
6x - 2x = 2x + 24 - 2x
4x = 25
Then, we divide by 4:
4x/4 = 24/4
x = 24/4 = 6
Now, we can see if we have done it correctly:
3 + 6*6 = 39
2 * 6 + 27 = 39
And we have seen our result is correct
Answer:
Mean = 78.2
Standard deviation = 5.8
Step-by-step explanation:
Mathematically z-score;
= (x-mean)/SD
From the question;
12% of test scores were above 85
Thus;
P( x > 85) = 12%
P(x > 85) = 0.12
Now let’s get the z-score that has a probability of 0.12
This can be obtained from the standard normal distribution table and it is = 1.175
Thus;
1.175 = (85 - mean)/SD
let’s call the mean a and the SD b
1.175 = (85-a)/b
1.175b = 85 - a
a = 85 - 1.175b ••••••••(i)
Secondly 8% of scores were below 70
Let’s find the z-score corresponding to this proportion;
We use the standard normal distribution table as usual;
P( x < 70) = 0.08
z-score = -1.405
Thus;
-1.405 =( 70-a)/b
-1.405b = 70-a
a = 70 + 1.405b ••••••(ii)
Equate the two a
70 + 1.405b = 85 - 1.175b
85 -70 = 1.405b + 1.175b
15 = 2.58b
b = 15/2.58
b = 5.81
a = 70 + 1.405b
a = 70 + 1.405(5.81)
a = 78.16
So mean = 78.2 and Standard deviation is 5.8
Answer:
the answer is 32
Step-by-step explanation:
hope this help have a good day
Answer:
<h3>First answer is correct</h3>
Step-by-step explanation:
156 dollars because 13 times 12 (months)
equals 156