Answer:
may we please have some more info on the question?
Step-by-step explanation:
Answer:
the common ratio is either 2 or -2.
the sum of the first 7 terms is then either 765 or 255
Step-by-step explanation:
a geometric sequence or series of progression (these are the most common names for the same thing) means that every new term of the sequence is created by multiplying the previous term by a constant factor which is called the common ratio.
so,
a1
a2 = a1×f
a3 = a2×f = a1×f²
a4 = a3×f = a1×f³
the problem description here tells us
a3 = 4×a1
and from above we know a3 = a1×f².
so, f² = 4
and therefore the common ratio = f = 2 or -2 (we need to keep that in mind).
again, the problem description tells us
a2 + a4 = 30
a1×f + a1×f³ = 30
for f = 2
a1×2 + a1×2³ = 30
2a1 + 8a1 = 30
10a1 = 30
a1 = 3
for f = -2
a1×-2 + a1×(-2)³ = 30
-10a1 = 30
a1 = -3
the sum of the first n terms of a geometric sequence is
sn = a1×(1 - f^(n+1))/(1-f) for f <>1
so, for f = 2
s7 = 3×(1 - 2⁸)/(1-2) = 3×-255/-1 = 3×255 = 765
for f = -2
s7 = -3×(1 - (-2)⁸)/(1 - -2) = -3×(1-256)/3 = -3×-255/3 =
= -1×-255 = 255
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
![M = Ts = 1.812*1.2060 = 2.19/tex]For the lower end of the interval, we subtract the sample mean by M. So the lower end of the interval here is[tex]L = 97 - 2.19 = 94.81 = 94.8](https://tex.z-dn.net/?f=M%20%3D%20Ts%20%3D%201.812%2A1.2060%20%3D%202.19%2Ftex%5D%3C%2Fp%3E%3Cp%3E%3Cstrong%3EFor%20the%20lower%20end%20of%20the%20interval%2C%20we%20subtract%20the%20sample%20mean%20by%20M.%3C%2Fstrong%3E%20So%20the%20lower%20end%20of%20the%20interval%20here%20is%3C%2Fp%3E%3Cp%3E%5Btex%5DL%20%3D%2097%20-%202.19%20%3D%2094.81%20%3D%2094.8)
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).
The value of the expression 8 / m - 11 / 3m is 13 / 3m
<h3 /><h3>How to simplify an expression?</h3>
8 / m - 11 / 3m
Therefore,
8 / m - 11 / 3m
The factor of the denominator is 3m
Therefore,
8 / m - 11 / 3m = 3(8) - 11/ 3m
3(8) - 11/ 3m = 24 - 11 / 3m
24 - 11 / 3m = 13 / 3m
learn more on fraction here: brainly.com/question/24161414
#SPJ1
Set up a proportion. 2/5 = x/40
to solve the equation first cross multiply.
x*5=40*2
x*5=80
now divide both sides by 5, 80 divided by 5 is equal to 16.
so the number of girls in the computer lab is 16.
