Answer:
2. x = 47
3. x = 2
Step-by-step explanation:
These problems involve proportions, or equivalent ratios. You can solve for 'x' in each by using cross-multiplication and division.
2. 28(7) = 4(x + 2)
Distribute = 196 = 4x + 8
Subtract 8 from both sides: 196 - 8 = 4x + 8 - 8 or 188 = 4x
Solve for x: x = 47
3. 2(2x + 7) = 11(3x - 4)
Distribute: 4x + 14 = 33x - 44
Add 44 to both sides: 4x + 14 + 44 = 33x - 44 + 44 or 4x + 58 = 33x
Subtract 4x from both sides: 4x + 58 - 4x = 33x - 4x or 58 = 29x
Solve for x: x = 2
Answer:
<em>There are 12 boys and 18 girls</em>
Step-by-step explanation:
<u>Equations</u>
There are 30 students in a class. Let's call:
x = number of boys
Since the sum of boys and girls is 30:
30 - x = number of girls
The ratio of boys to girls is 2:3, thus:

Crossing denominators:
3x = 2(30 - x)
Operating the parentheses:
3x = 60 - 2x
Adding 2x:
5x = 60
Dividing by 5:
x = 60/5 = 12
x = 12
There are 12 boys and 30-12=18 girls
2x+3y-10=0 (1)
+
4x-3y-2=0 (2)
____________
6x -12=0 (if you just want the resulting equation. It is 6x-12=0)
x=2
take x=2 and put it into equation (2)
4(2) -3y -2=0
-3y= 2-8
y= 2
(x=2,y=2)
90. The measure of an inscribed angle is half of that of the measure of its arc, and the measure of the angle corresponding with arc a is 45. 45*2 is 90, so 90 is the measure of arc a.
Answer:
95% two-sided confidence interval on the true mean breaking strength is (94.8cm, 99.2cm)
Step-by-step explanation:
Our sample size is 11.
The first step to solve this problem is finding our degrees of freedom, that is, the sample size subtracted by 1. So
.
Then, we need to subtract one by the confidence level
and divide by 2. So:

Now, we need our answers from both steps above to find a value T in the t-distribution table. So, with 10 and 0.025 in the two-sided t-distribution table, we have 
Now, we find the standard deviation of the sample. This is the division of the standard deviation by the square root of the sample size. So

Now, we multiply T and s
cm
For the upper end of the interval, we add the sample mean and M. So the upper end of the interval here is
cm
So
95% two-sided confidence interval on the true mean breaking strength is (94.8cm, 99.2cm).