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3 years ago

HCF(320, x) = 20, LCM(320, x) = 2240, then x =

Mathematics

1 answer:

HACTEHA [7]3 years ago

6 0

Answer:

140

Step-by-step explanation:

When working HCF and LCM problems, I like to think in terms of this little diagram:

(a [ b ) c]

It shows me one of the numbers is ab, the other is bc, the HCF is b and the LCM is abc. "a" and "c" must be relatively prime for "b" to be the HCF.

Here, we're given ...

b = 20

ab = 320

abc = 2240

Then ...

c = abc/(ab) = 2240/320 = 7

x = bc = 20(7) . . . . . . equivalently, x = (abc·b)/(ab) = (2240·20)/320

x = 140

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Answer:

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Step-by-step explanation:

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2 years ago

For all real numbers a and b, a+b=b+a

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3 years ago

If a test of H subscript 0 colon space mu subscript D equals 0 space v s. space H subscript a colon space space mu subscript D g

lara [203]

Answer:

$p_v =P(t_{(n-1)}>t_{calculated}) =0.0601$

The p value on this case is given by the problem.

If we compare the p value with a significance level assumed $\alpha=0.05$ , we see that $p_v > \alpha$ and we can conclude that we FAIL to reject the null hypothesis that the difference mean between after and before is less or equal than 0.

Step-by-step explanation:

A paired t-test is used to compare two population means where you have two samples in which observations in one sample can be paired with observations in the other sample. For example if we have Before-and-after observations (This problem) we can use it.

Let put some notation

x=test value before , y = test value after

The system of hypothesis for this case are:

Null hypothesis: $\mu_y- \mu_x \leq 0$

Alternative hypothesis: $\mu_y -\mu_x >0$

The first step is calculate the difference $d_i=y_i-x_i$

The second step is calculate the mean difference

$\bar d= \frac{\sum_{i=1}^n d_i}{n}$

The third step would be calculate the standard deviation for the differences, and we got:

$s_d =\frac{\sum_{i=1}^n (d_i -\bar d)^2}{n-1}$

The 4 step is calculate the statistic given by :

$t=\frac{\bar d -0}{\frac{s_d}{\sqrt{n}}}=t_{calculated}$

The next step is calculate the degrees of freedom given by:

$df=n-1$

Now we can calculate the p value, since we have a right tailed test the p value is given by:

$p_v =P(t_{(n-1)}>t_{calculated}) =0.0601$

The p value on this case is given by the problem.

4 0

3 years ago

Q2.What is the ratio of volumes of the two cylinders formed by rolling a sheet of dimensions lxb in two different ways? Q3.What

Kobotan [32]

Answer:

2. b : l

3. 20cm

4. 49 $cm^{2}$

5. $(2\pi+1):2\pi$

Step-by-step explanation:

Solution 2:

Let cylinder is rolled along 'l':

Height of cylinder , h = length of rectangle = l

Perimeter of base = b

Let 'r' be the radius of cylinder's base:

$2\pi r = b\\\Rightarrow r = \dfrac{b}{2\pi}$

Volume of a cylinder is given as:

$V = \pi r^{2} h$

Putting the values:

$V_1 = \pi (\dfrac{b}{2\pi})^2 l\\\Rightarrow V_1 = (\dfrac{b^2}{4\pi}) l$

Let cylinder is rolled along 'b':

Height of cylinder , h = length of rectangle = b

Perimeter of base = l

Let 'r' be the radius of cylinder's base:

$2\pi r = l\\\Rightarrow r = \dfrac{l}{2\pi}$

Volume of a cylinder is given as:

$V = \pi r^{2} h$

Putting the values:

$V_2 = \pi (\dfrac{l}{2\pi})^2 b\\\Rightarrow V_2 = (\dfrac{l^2}{4\pi}) b$

Taking ratio:

$V_1:V_2 = \dfrac{(\dfrac{b^2}{4\pi}) l}{(\dfrac{l^2}{4\pi}) b} = b:l$

Solution 3:

Rectangle is rolled along its length to make a cylinder, so height will be equal to its length.

$\therefore$ height of cylinder = 20 cm

Solution 4:

Side of square = 7 cm

Height of cylinder =Side of square = 7 cm

7 cm will be the circumference of the circle.

i.e. $2\pi r$ = 7 cm

Curved surface area of a cylinder:

$CSA = 2\pi rh$

Putting the above values:

CSA = 7 $\times$ 7 = 49 $cm^{2}$

Solution 5:

As calculated in above step:

CSA = $2\pi rh =$ 7 $\times$ 7 = 49 $cm^{2}$

Total surface area = $2\pi r^{2} + 2\pi r h$

Calculating value of r:

$2\pi r$ = 7 cm

$\Rightarrow 2 \pi r = 7\\\Rightarrow r = \dfrac{7}{2\pi}$

Total surface area =

$2\pi (\dfrac{7}{2\pi})^{2} + 49\\\Rightarrow \dfrac{49}{2\pi}+49\\\Rightarrow 49(\dfrac{1}{2\pi}+1) cm^2$

Ratio of TSA: CSA is

$49(\dfrac{1}{2\pi}+1) cm^2 : 49 cm^2\\\Rightarrow (\dfrac{1}{2\pi}+1):1\\\Rightarrow (2\pi+1): 2\pi$

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3 years ago

Least to greatest 0.94,9.40,0.094,94.0,94.0

sertanlavr [38]

Here's an example number:
123.456
The place values are, from greatest to least:
The 1 is in the hundreds place
The 2 is in the tens place
The 3 is in the ones place
The 4 is in the tenths place
The 5 is in the hundredths place

If you have some number like 9.40 with no decimal point, shifting it will change the value. Moving the decimal one place to the right multiplies the value by ten. (94)
Moving it one place to the rigt divides it by ten. (0.94)

Here's our list from least to greatest:
94.0
9.40
0.94
0.094

5 0

3 years ago