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3 years ago

What is the x value for 21x+7y=42

Mathematics

2 answers:

xz_007 [3.2K]3 years ago

6 0

Step-by-step explanation: The letter "x" is often used in algebra to mean a value that is not yet known. It is called a "variable" or sometimes an "unknown". In x + 2 = 7, x is a variable, but we can work out its value if we try!

Andreyy893 years ago

5 0

The value of X is 1.66 repeated ?

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A person suspects a standard number cube is not so standard. Another person rolls this cube 100 times, and it lands on a six 42

Ksju [112]

Answer:

The chance of an average six-sided number cube landing one one number is 1/6, or approximately 16.67%. When rolling a number cube 100 times, the average number of times it lands on any specific number should be fairly close to 16.67.

A 6 being rolled 42 times and 33 times means that it is <em>very likely</em> not to be a standard number cube. Although we cannot know for certain, the chance of this happening is very low.

3 0

3 years ago

How many square feet of outdoor carpet will we need for this hole

Fed [463]

Answer:

40 ft²

Step-by-step explanation:

The shape of the outdoor carpet can be decomposed into 2 triangles and 1 rectangle

✔️Area of triangle 1:

Area = ½*bh

b = 6 - 3 = 3 ft

h = 11 - 7 = 4 ft

Area of triangle 1 = ½*3*4 = 6 ft²

✔️Area of triangle 2:

Area = ½*by

b = 2 ft

h = 3 ft

Area of triangle 2 = ½*2*3 = 3 ft

✔️Area of rectangle = L × W

L = 11 ft

W = 3 ft

Area of rectangle = 11 × 3 = 33 ft

✅area of outdoor carpet = 4 + 3 + 33 = 40 ft²

4 0

3 years ago

Why 10^33/2=5*10^32? Explain, pls. :(

german

Answer:

see below

Step-by-step explanation:

10^33/2

Rewriting the numerator as 10 * 10 ^ 32

10 * 10 ^32

--------------------

10/2 = 5

5 * 10 ^32

Therefore

10^33/2=5*10^32

4 0

2 years ago

Kenneth bought a new roll of tape. There were 59.6 yards of tape on the roll. Then Kenneth used 4 yards of the tape to make a co

barxatty [35]

Answer:

55.6 yards

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

Two machines are used for filling glass bottles with a soft-drink beverage. The filling process have known standard deviations s

stellarik [79]

Answer:

a. We reject the null hypothesis at the significance level of 0.05

b. The p-value is zero for practical applications

c. (-0.0225, -0.0375)

Step-by-step explanation:

Let the bottles from machine 1 be the first population and the bottles from machine 2 be the second population.

Then we have $n_{1} = 25$ , $\bar{x}_{1} = 2.04$ , $\sigma_{1} = 0.010$ and $n_{2} = 20$ , $\bar{x}_{2} = 2.07$ , $\sigma_{2} = 0.015$ . The pooled estimate is given by

$\sigma_{p}^{2} = \frac{(n_{1}-1)\sigma_{1}^{2}+(n_{2}-1)\sigma_{2}^{2}}{n_{1}+n_{2}-2} = \frac{(25-1)(0.010)^{2}+(20-1)(0.015)^{2}}{25+20-2} = 0.0001552$

a. We want to test $H_{0}: \mu_{1}-\mu_{2} = 0$ vs $H_{1}: \mu_{1}-\mu_{2} \neq 0$ (two-tailed alternative).

The test statistic is $T = \frac{\bar{x}_{1} - \bar{x}_{2}-0}{S_{p}\sqrt{1/n_{1}+1/n_{2}}}$ and the observed value is $t_{0} = \frac{2.04 - 2.07}{(0.01246)(0.3)} = -8.0257$ . T has a Student's t distribution with 20 + 25 - 2 = 43 df.

The rejection region is given by RR = {t | t < -2.0167 or t > 2.0167} where -2.0167 and 2.0167 are the 2.5th and 97.5th quantiles of the Student's t distribution with 43 df respectively. Because the observed value $t_{0}$ falls inside RR, we reject the null hypothesis at the significance level of 0.05

b. The p-value for this test is given by $2P(T$ 0 (4.359564e-10) because we have a two-tailed alternative. Here T has a t distribution with 43 df.

c. The 95% confidence interval for the true mean difference is given by (if the samples are independent)

$(\bar{x}_{1}-\bar{x}_{2})\pm t_{0.05/2}s_{p}\sqrt{\frac{1}{25}+\frac{1}{20}}$ , i.e.,

$-0.03\pm t_{0.025}0.012459\sqrt{\frac{1}{25}+\frac{1}{20}}$

where $t_{0.025}$ is the 2.5th quantile of the t distribution with (25+20-2) = 43 degrees of freedom. So

$-0.03\pm(2.0167)(0.012459)(0.3)$ , i.e.,

(-0.0225, -0.0375)

8 0

3 years ago