Answer: 31/12, or 2 7/12
Step-by-step explanation: The answer is actually very simple. All you have to do is to simplify 10 1/3 into 31/3, as 10x3+1=31. Then, you have to multiply 31/3 with 1/4. Do a simple fraction multiplication, and you get 31/12, or 2 7/12 if your teacher is asking for a mixed number. Sometimes simplifying is better
Answer:
B. yes.
Step-by-step explanation:
dd_rrdrdy]uuhhhgffdddddddddddddddddddddd
Answer:
The numbers are 12, 21.
Step-by-step explanation:
x+(x+9)=33
x+x+9=33
2x+9=33
2x=33-9
2x=24
x=24/2
x=12
--------
x+9=12+9=21
Please mark me as Brainliest if you're satisfied with the answer.
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
