Richard earns $25 allowance each week how can she mentally compute her total earnings after seven weeks

Please helppp ppppñpñp

Dahasolnce [82]

Answer:

I tried my best to explain it, hope it helps!

Step-by-step explanation:

8 0

3 years ago

1. De una encuesta realizada a 120 personas sobre el consumo de albaricoque, banana y coco se obtuvieron el siguiente resultado.

Pachacha [2.7K]

Answer:

El número de personas que consumen dos productos es 30.

Step-by-step explanation:

El primer paso para resolver el problema es realizar los gráficos de los eventos (agregaré como archivo adjunto el gráfico del ejercicio).

En el gráfico podemos ver 7 regiones :

A : Personas que consumen sólo albaricoque.

B : Personas que consumen sólo banana.

C : Personas que consumen sólo coco.

D : Personas que consumen sólo albaricoque y coco.

E : Personas que consumen las tres frutas (albaricoque, banana y coco).

F : Personas que consumen sólo banana y coco.

G : Personas que consumen sólo albaricoque y banana.

Ahora, debemos escribir las ecuaciones que nos brinda el ejercicio :

La encuesta se realizó a 120 personas y se sabe que todas las personas consumen un producto ⇒

$A+B+C+D+E+F+G=120$ (I)

''El número de personas que consumen sólo albaricoque y coco es la mitad de las que consumen sólo albaricoque'' ⇒

$D=\frac{A}{2}$ (II)

''El número de personas que consumen sólo banana es el doble de las personas que consumen sólo albaricoque y banana más sólo banana y coco'' ⇒

$B=2.(G+F)$ (III)

Finalmente : ''El número de personas que consumen sólo coco más los que consumen los tres productos es 30'' ⇒

$C+E=30$ (IV)

Finalmente obtenemos el siguiente sistema de ecuaciones :

$A+B+C+D+E+F+G=120\\D=\frac{A}{2}\\B=2.(G+F)\\C+E=30$

El número de personas que consumen dos productos es :

$D+F+G$

Entonces, resolvemos escribiendo la primera ecuación conmutando los términos :

$A+B+C+E+D+F+G=120$ (V)

De (II) se obtiene :

$2D=A$ (VI)

Usamos (VI), (III) y (IV) en (V) ⇒

$2D+2(G+F)+30+D+F+G=120$ ⇒

$2D+2G+2F+30+D+F+G=120$

$3D+3F+3G=90$

Dividiendo esta última ecuación por ''3'' obtenemos :

$D+F+G=30$

Que es el número de personas que consumen dos productos.

Es muy conveniente seguir el desarrollo del ejercicio mirando el gráfico que adjunto.

8 0

3 years ago

-2/5n = -30 n=<br><br> can some one help pleaasee

kirill115 [55]

-2/5n=-30n
multiply both sides by -1 sinc I don' like negatives
2/5n=30n
multipl yboth sides by 5/2
1n=150/2n
n=75n
this is obviously false, the only number that would work is 0 since 0 =0 times 75

n=0

4 0

3 years ago

The Municipal Transit Authority wants to know if, on weekdays, more passengers ride the northbound blue line train towards the c

Kitty [74]

Answer:

The 90% confidence interval $-49.8$

The null hypothesis is $H_o : \mu_1 = \mu_2$

The alternative hypothesis $H_a : \mu_1 < \mu_2$

The distribution test statistics is $t = -3.222$

The rejection region is p-value < $\alpha$

The decision rule is reject the null hypothesis

The conclusion is

There is sufficient evidence to conclude that there are more passengers riding the 8:30 train

The p-value is $p-value =0.000951$

Step-by-step explanation:

From the question we are told that

The first sample size $n_1 = 30$

The first sample mean is $\= x _1 = 323$

The first standard deviation is $s_1 = 41$

The second sample size is $n_2 = 45$

The second sample mean is $\=x_2 = 356$

The second standard deviation is $s_2 = 45$

given that the confidence level is 90% then the level of significance is mathematically represented as

$\alpha = (100 -90)\%$

$\alpha = 0.10$

Generally the critical value of $\frac{\alpha }{2}$ obtained from the normal distribution table is

$Z_{\frac{\alpha }{2} } = 1.645$

Generally the pooled variance is mathematically represented as

$s^2 = \frac{(n_1 - 1)s_1^2 + (n_2 -1)s_2^2 }{n_1 + n_2 -2}$

$s^2 = \frac{(30 -1)(41^2) + (45-1)45^2}{30+45 -2}$

$s^2 = 1888.34$

Generally the standard error is mathematically represented as

$SE = \sqrt{\frac{s^2}{n_1} + \frac{s^2}{n_2} }$

=> $SE = \sqrt{\frac{1888.34}{30} + \frac{1888.34}{45} }$

=> $SE = 10.24$

Generally the margin of error is mathematically evaluated as

$E = Z_{\frac{\alpha }{2} } * SE$

$E = 1.645* 10.24$

$E = 16.85$

Generally the 90% confidence interval is mathematically represented as

$\=x_1 -\=x_2 -E < \mu_1 -\mu_2 < \=x_1 -\=x_2 +E$

$323 -356 -16.84$

$-49.8$

The null hypothesis is $H_o : \mu_1 = \mu_2$

The alternative hypothesis $H_a : \mu_1 < \mu_2$

Generally the test statistics is mathematically represented as

$t = \frac{\= x_1 - \=x_2 }{SE}$

=> $t = \frac{323-356}{10.24}$

=> $t = -3.222$

Generally the degree of freedom is mathematically represented as

$df = n_1+n_2 -2$

$df = 30 + 45 -2$

$df = 73$

The p-value is obtained from the student t distribution table at degree of freedom of 73 at 0.05 level of significance

The value is $p-value =0.000951$

Here the level of significance is $\alpha = 5\% = 0.05$

Given that the p-value < $\alpha$ then we reject the null hypothesis

Then the conclusion is

There is sufficient evidence to conclude that there are more passengers riding the 8:30 train

5 0

3 years ago

<img src="https://tex.z-dn.net/?f=%20%5Csqrt%7B2x%20%2B%201%20%7D%20%20%3D%20x%20-%201" id="TexFormula1" title=" \sqrt{2x + 1 }

Nonamiya [84]

X Is equal to 4 ..........................

3 0

3 years ago