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4 years ago

Fifteen more than three times a number is 45

Mathematics

1 answer:

BlackZzzverrR [31]4 years ago

8 0

First, put it in an equation.

(x*3) + 15 = 45

10 * 3 = 30

30 + 15 = 45

Now plug it in to double check:

(10 * 3) + 15 = 45

30 + 15 = 45

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Choose a number from 101 to 110 write it draw a picture to show it as 10 tens and more.

MrMuchimi

You would do ten columns of ten and then you would just do the remaining.

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3 years ago

Using diaries for many weeks, a study on the lifestyles of visually impaired students was conducted. The students kept track of

Hoochie [10]

Answer:

a) 0.1020

b) 0.7125

c) 7.64 hours

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 8.65, \sigma = 1.93$

(a) What is the probability that a visually impaired student gets less than 6.2 hours of sleep?

This is the pvalue of Z when X = 6.2. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{6.2 - 8.65}{1.93}$

$Z = -1.27$

$Z = -1.27$ has a pvalue of 0.1020.

So the answer for a is 0.1020.

(b) What is the probability that a visually impaired student gets between 6.8 and 10.93 hours of sleep?

This is the pvalue of Z when X = 10.93 subtracted by the pvalue of Z when X = 6.8. So

X = 10.93

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{10.93 - 8.65}{1.93}$

$Z = 1.18$

$Z = 1.18$ has a pvalue of 0.8810.

X = 6.8

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{6.8 - 8.65}{1.93}$

$Z = -0.96$

$Z = -0.96$ has a pvalue of 0.1685.

So the answer for b) is 0.8810 - 0.1685 = 0.7125.

(c) Thirty percent of students get less than how many hours of sleep on a typical day?

This is the value of X in the 30th percentile, that is, the value of X when Z has a pvalue of 0.30. So it is X when Z = -0.525, since this happens between Z = -0.53 and Z = -0.52.

$Z = \frac{X - \mu}{\sigma}$

$-0.525 = \frac{X - 8.65}{1.93}$

$X - 8.65 = -0.525*1.93$

$X = 7.64$

The answer for c is 7.64 hours.

3 0

3 years ago

VA Tech offers four applied majors and monitors the number of students in each.

adelina 88 [10]

Answer:

Step-by-step explanation:

Number of students in electronics, 1/4 of the total

36*1/4 = 9

Number of students in architecture, 1/6 of the total

36*1/6 = 6

The difference is

9 - 6 = 3

5 0

3 years ago

Find the area of a circle with a radius of 8.6cm. Round to the nearest hundredth.

SOVA2 [1]

Answer:

Step-by-step explanation:since i helped can i have brainlist please :D

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3 years ago

Jimmy wants to enlarge a sign for his taco stand. He increases the height by a scale factor of 4 and the width by a factor of 2.

icang [17]

After the increase in the dimensions of the sign, the effect on the area of the sign is that the new area is 8 times larger than the initial area.

The sign has the shape of a rectangle. A rectangle has four sides. The opposite sides are equal in length.

The area of a rectangle = length x width.

Jimmy is making the sign bigger by increasing the size of the length and width. Let's imagine that the width is 8cm and the length is 10cm.

The initial area of the sign = 10 x 8 = 80 cm

After the increase in the dimensions, the length is are 40cm and 16cm for the width.

New area = 40 x 16 = 640

Number of times the new area is greater than the initial area = 640 / 80 = 8 times larger

A similar question was answered here: brainly.com/question/18452788

7 0

3 years ago