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sergiy2304 [10]
3 years ago
14

Logs are stacked in a pile. The bottom row has 50 logs and next to bottom row has 49 logs. Each row has one less log than the ro

w below it. How many logs will be there in 5th row? Use the recursive formula.
Mathematics
1 answer:
Mars2501 [29]3 years ago
8 0

Answer:

46 logs on the 5th row.

Step-by-step explanation:

Number of logs on the nth row is

n =  50 - (n-1)

 n = 51 - n    (so on the first row we have  51 - 1 = 50 logs).

So on the 5th row we have 51 - 5 = 46 logs.

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A line passes through the two points: (1, 10) and (6,5).
Snowcat [4.5K]

Answer:

<em>(a). - 1 ; (b). y = - x + 11</em>

Step-by-step explanation:

(1, 10)

(6, 5)

<em>(a).</em> <em>m</em> = \frac{y_{2} -y_{1} }{x_{2} -x_{1} } = \frac{5-10}{6-1} = <em>- 1</em>

<em>(b).</em> y - 5 = - 1(x - 6)

<em>y = - x + 11</em>

5 0
3 years ago
Simplification <br>-4a+b+3c+3a-3b+c​
damaskus [11]

Answer:

-a+-2b+4c

Step-by-step explanation:

Combine like terms

-4a+ 3a= -a

b+ -3b= -2b

3c+ c= 4c

7 0
2 years ago
Exercise 11.21) Many smartphones, especially those of the LTE-enabled persuasion, have earned a bad rap for exceptionally bad ba
stiv31 [10]

Answer:

Step-by-step explanation:

Hello!

The researcher suspects that the battery life between charges for the Motorola Droid Razr Max differs if its primary use is talking or if its primary use is for internet applications.

Since the means for talk time usage (20hs) is greater than the mean for internet usage (7hs) the main question is if the variance in hours of usage is also greater when the primary use is talk time.

Be:

X₁: Battery duration between charges when the primary usage of the phone is talking. (hs)

n₁= 12

X[bar]₁= 20.50 hs

S₁²= 199.76hs² (S₁= 14.13hs)

X₂: Battery duration between charges when the primary usage of the phone is internet applications.

n₂= 10

X[bar]₂= 8.50

S₂²= 33.29hs² (S₂= 5.77hs)

Assuming that both variables have a normal distribution X₁~N(μ₁;σ₁²) and X₂~N(μ₂; σ₂²)

The parameters of interest are σ₁² and σ₂²

a) They want to test if the population variance of the duration time of the battery when the primary usage is for talking is greater than the population variance of the duration time of the battery when the primary usage is for internet applications. Symbolically: σ₁² > σ₂² or since the test to do is a variance ratio: σ₁²/σ₂² > 1

The hypotheses are:

H₀: σ₁²/σ₂² ≤ 1

H₁: σ₁²/σ₂² > 1

There is no level of significance listed so I've chosen α: 0.05

b) I've already calculated the sample standard deviations using a software, just in case I'll show you how to calculate them by hand:

S²= \frac{1}{n-1}*[∑X²-(∑X)²/n]

For the first sample:

n₁= 12; ∑X₁= 246; ∑X₁²= 7240.36

S₁²= \frac{1}{11}*[7240.36-(246)²/12]= 199.76hs²

S₁=√S₁²=√199.76= 14.1336 ≅ 14.13hs

For the second sample:

n₂= 10; ∑X₂= 85; ∑X₂²= 1022.12

S₂²= \frac{1}{9}*[1022.12-(85)²/10]= 33.2911hs²

S₂=√S₂²=√33.2911= 5.7698 ≅ 5.77hs

c)

For this hypothesis test, the statistic to use is a Snedecors F:

F= \frac{S_1^2}{S_2^2} *\frac{Sigma_1^2}{Sigma_2^2} ~~F_{n_1-1;n_2-1}

This test is one-tailed right, wich means that you'll reject the null hypothesis to big values of F:

F_{n_1-1;n_2-1; 1-\alpha }= F_{11;9;0.95}= 3.10

The rejection region is then F ≥ 3.10

F_{H_0}= \frac{199.76}{33.29} * 1= 6.0006

p-value: 0.006

Considering that the p-value is less than the level of significance, the decision is to reject the null hypothesis.

Then at a 5% level, there is significant evidence to conclude that the population variance of the duration time of the batteries of Motorola Droid Razr Max smartphones used primary for talk is greater than the population variance of the duration time of the batteries of Motorola Droid Razr Max smartphones used primary for internet applications.

I hope this helps!

8 0
2 years ago
Please help !!! brainliest will be given
sattari [20]

Answer:

6 is the domain because it is always the x value while range is the y value.

7 0
3 years ago
Read 2 more answers
A company sells tents in two styles, shown below. The sides and floor of each tent are made of nylon. Which tent requires less n
BartSMP [9]

Answer:  Tunnel tent.

Step-by-step explanation:

The tent which has the minimum area requires less nylon to manufacture,

Since, the area of Pup tent = Area of 3 square each having side 8 ft + Area of 2 equilateral triangle having side 8 ft

= 3 \times ( 8^2 ) + 2\times \frac{64\sqrt{ 3} }{4}

=  192+ 2\times \frac{64\sqrt{ 3} }{4}

= 192+ 32\sqrt{ 3}

= 247.425625842\approx 247.43\text { square ft}

Now, the area of tunnel tent = Area of square having side 8 ft + total Area of half cylinder having radius 4 ft and height 8 ft

= 8^2 + \frac{1}{2} [ 2\pi\times 4(4+8)]

= 64 + \pi\times 48

= 64 + 3.14\times 48

= 214.72\text { square ft}

Since, 214.72 < 247.43

Thus, Tunnel tent requires less nylon to manufacture.

4 0
3 years ago
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