After a 15% off sale,some jeans were $11.50.How much were the jeans before the sale?

Alona [7]

Answer:

The lower limit is 75.04

The upper limit is 78.96

Step-by-step explanation:

From the question we are told that

The sample size is $n = 25$

The sample mean is $\= x = 77$

The standard deviation is $\sigma = 5$

Given that the confidence level is 95% then the level of significance is mathematically represented as

$\alpha = (100 - 95)\%$

$\alpha = 0.05$

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

$Z_{\frac{\alpha }{2} } = 1.96$

Generally the margin of error is mathematically represented as

$E = Z_{\frac{\alpha }{2} } * \frac{\sigma }{\sqrt{n} }$

=> $E = 1.96* \frac{5 }{\sqrt{25} }$

=> $E = 1.96$

The 95% confidence interval is mathematically represented as

$\= x -E < \mu < \= x +E$

=> $77 - 1.96 < \mu < 77 + 1.96$

=> $75.04 < \mu < 78.96$

7 0

2 years ago

What is the area of the rectangle?

RideAnS [48]

Length=L=3cm
Breadth=B=2cm

Area

Length ×Breadth
3(2)
6cm²

7 0

2 years ago

The triangles shown below must be congruent.

leonid [27]

These triangles are congruent by AAS condition hence the statement is true

7 0

3 years ago

Read 2 more answers

in mrs. wallace class's science class, 1/2 of the students are boys. Of the boys , 1/8 are left- handed. what fraction of the st

o-na [289]

Answer:

1/16 of the class are left handed boys but we do not know the amount of left handed girls so we cannot be sure.

Step-by-step explanation:

1/2 * 1/8 = 1/16

there is still no way to be sure of how many girls are left handed so you should probably make a note by the problem so the mistake on the test will be realized

4 0

3 years ago

At the beginning of the semester students reported that they spend an average of 5 hours per day watching television, decreasing

Katyanochek1 [597]

Answer:

(a) $X(t)=X(0)+\Delta X*t=5-0.5*t$

(b) $X(t)=X(0)+\Delta X*t=1+0.5*t$

(c) At 4 weeks, when both will be seeing an average of 3 hours of TV.

Step-by-step explanation:

a) For the students, they start at X(0)=5 h and ΔX=-0.5 h/week.

We can write

$X(t)=X(0)+\Delta X*t=5-0.5*t$

b) For the professors, they start at X(0)=1 h and ΔX=+0.5 h/week.

We can write

$X(t)=X(0)+\Delta X*t=1+0.5*t$

c) The seew which they will be watching the same amount of hours will be the 4th week.

$X(t)=5-0.5*t=1+0.5*t\\\\5-1=(0.5+0.5)*t\\\\t=4\, weeks$

The amount of hours will be

$x(4)=1+0.5*4=1+2=3\,hours$

7 0

3 years ago