All categories

3 years ago

A family is taking a cross country trip by car. They drive at an average speed of 55/mi/h, and their goal is to travel at least

400 mi/day. How many hours per day do they need to drive?

Mathematics

1 answer:

Anestetic [448]3 years ago

7 0

$400mi \times \frac{1h}{55mi} \approx 7.27h \ (exact:\ \frac{80}{11}\ or\ 7\frac{3}{11})$

You might be interested in

Given Sin x= 0.5, what is cos x?

Svetllana [295]

Sin x = 0.5
sin x = 1/2
sin x = opp/hyp
therefore the ratio of opp/hyp = 1/2, (opp = 1, hyp = 2)

Find the opp side

1² + x² = 2²
1 + x² = 4
x² = 4 -1
x² = 3
x =√3

The opp side is √3

cos x = opp/hyp = √3/2 = 0.87 (round to the nearest hundredths)

3 0

3 years ago

The lines below are parallel. If the slope of the green line is -2, what is the

Andreas93 [3]

Answer:

C. -2

Step-by-step explanation:

All parallel lines have the same slope

4 0

3 years ago

A bag containing food has mass 3.813 kg. When the bag is empty its mass is 257 g. Find in kilograms the mass of the fruit

Elden [556K]

Answer:

I think it is 0.257 kg

Step-by-step explanation:

To change units from the gram to kilogram, you need to divide by 1000, because 1kg=1000g:

257÷1000= 0.257 Kg

5 0

3 years ago

Measure the length of AD & D B what is the ratio of AD to DB

ludmilkaskok [199]

Based on the calculations, the ratio of AD to DB is equal to 0.6.

<h3>What is a ratio?</h3>

A ratio is a mathematical expression that's used to denote the proportion of two (2) or more quantities with respect to one another and the total quantities.

From the graph, we have:

Length of AD = 1.5

Length of DB = 2.5

Ratio = AD/DB

Ratio = 1.5/2.5

Ratio = 0.6.

Read more on ratio here: brainly.com/question/13513438

#SPJ1

8 0

2 years ago

A simple random sample of 28 Lego sets is obtained and the number of pieces in each set was counted.The sample has a standard de

Karo-lina-s [1.5K]

Answer:

Step-by-step explanation:

Given that:

A simple random sample n = 28

sample standard deviation S = 12.65

standard deviation $\sigma$ = 11.53

Level of significance ∝ = 0.05

The objective is to test the claim that the number of pieces in a set has a standard deviation different from 11.53.

The null hypothesis and the alternative hypothesis can be computed as follows:

Null hypothesis:

$H_0: \sigma^2 = \sigma_0^2$

Alternative hypothesis:

$H_1: \sigma^2 \neq \sigma_0^2$

The test statistics can be determined by using the following formula in order to test if the claim is statistically significant or not.

$X_0^2 = \dfrac{(n-1)S^2}{\sigma_0^2}$

$X_0^2 = \dfrac{(28-1)(12.65)^2}{(11.53)^2}$

$X_0^2 = \dfrac{(27)(160.0225)}{132.9409}$

$X_0^2 = \dfrac{4320.6075}{132.9409}$

$X_0^2 = 32.5002125$

$X^2_{1- \alpha/2 , df} = X^2_{1- 0.05/2 , n-1}$

$X^2_{1- \alpha/2 , df} = X^2_{1- 0.025 , 28-1}$

From the chi-square probabilities table at 0.975 and degree of freedom 27;

$X^2_{0.975 , 27}$ = 14.573

$X^2_{\alpha/2 , df} = X^2_{ 0.05/2 , n-1}$

$X^2_{\alpha/2 , df} = X^2_{0.025 , 28-1}$

From the chi-square probabilities table at 0.975 and degree of freedom 27;

$X^2_{0.025 , 27}=$ 43.195

Decision Rule: To reject the null hypothesis if $X^2_0 \ > \ X^2_{\alpha/2 , df} \ \ \ or \ \ \ X^2_0 \ < \ X^2_{1- \alpha/2 , df}$ ; otherwise , do not reject the null hypothesis:

The rejection region is $X^2_0 \ > 43.195 \ \ \ or \ \ \ X^2_0 \ < \ 14.573$

Conclusion:

We fail to reject the null hypothesis since test statistic value 32.5002125 lies between 14.573 and 43.195.

6 0

3 years ago