6.4x + 2.8y = 44.4
6.4(3) + 2.8y = 44.4
19.2 + 2.8y = 44.4
-19.2 -19.2
2.8y = 25.2
------ ------
2.8 2.8
y = 9
4y=-20+3x and 4y=13.6x-20
so
-20+3x=13.6x-20
3x=13.6x
3=13.6 so it is wrong and system doesn’t have solution
Answer:
y = 84
Step-by-step explanation:
1) add 3 to both sides of your equation to cancel out the -3
end up with: (1/3)y + 14 = (1/2)y
2) multiply both sides of your equation by 2 to cancel out the (1/2)
end up with: (2/3)y + 28 = y
3) subtract (2/3)y from both sides of the equation to cancel out the positive (2/3)y
end up with: 28 = (1/3)y
4) multiply both sides of the equation by 3 to cancel out the (1/3)
end up with: 84 = y
Answer:
the first sentance is wrong, the second one is right, the third one is right and the last one is wrong
Step-by-step explanation:
We have been given that the ages of students in a school are normally distributed with a mean of 15 years and a standard deviation of 2 years.
We are asked to find the percentage of students that are between 14 and 18 years old.
First of all, we will find z-score corresponding to 14 and 18 using z-score formula.
Similarly, we will find the z-score corresponding to 18.
Now we will find the probability of getting a z-score between 
and 
that is 
.
Using normal distribution table, we will get:
Let us convert 
into percentage.
Therefore, approximately 
of the students are between 14 and 18 years old.
