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2 years ago

A bookshelf is 3 ½ feet long. Each book on the shelf in ⅝ inches wide. How many books will fit on the shelf?

Mathematics

1 answer:

n200080 [17]2 years ago

8 0

Divide the width of the shelf by the widthof the books.

First rewrite feet as inches:

1 foot = 12 inches.

3 1/2 feet x 12 inches per foot = 42 inches

Now divide the width of the shelf by the width of the book:

Now you have 42 / 5/8

When dividing by a fraction flip the second fraction over and change division to multiplication:

42 x 8/5

Now Multiply across:

7/2 x 8/5 = (42 x 8) /5 = 336/5 = 67.2

Round to the nearest whole number: 67

The shelf will hold 67 books.

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How do you find the x?

AnnyKZ [126]

There are 180 degrees total in a triangle and the tell you one angle is 90. So you solve the equation 4x+6x=90. So x=9

3 0

3 years ago

Boxes of raisins are labeled as containing 22 ounces. Following are the weights, in the ounces, of a sample of 12 boxes. It is r

ZanzabumX [31]

Answer:

A 90% confidence interval for the mean weight is [21.78 ounces, 21.98 ounces].

Step-by-step explanation:

We are given the weights, in the ounces, of a sample of 12 boxes below;

Weights (X): 21.88, 21.76, 22.14, 21.63, 21.81, 22.12, 21.97, 21.57, 21.75, 21.96, 22.20, 21.80.

Firstly, the pivotal quantity for finding the confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean weight = $\frac{\sum X}{n}$ = 21.88 ounces

s = sample standard deviation = $\sqrt{\frac{\sum (X-\bar X)^{2} }{n-1} }$ = 0.201 ounces

n = sample of boxes = 12

$\mu$ = population mean weight

Here for constructing a 90% confidence interval we have used a One-sample t-test statistics because we don't know about population standard deviation.

So, 90% confidence interval for the population mean, $\mu$ is ;

P(-1.796 < $t_1_1$ < 1.796) = 0.90 {As the critical value of t at 11 degrees of

freedom are -1.796 & 1.796 with P = 5%}

P(-1.796 < $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ < 1.796) = 0.90

P( $-1.796 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $1.796 \times {\frac{s}{\sqrt{n} } }$ ) = 0.90

P( $\bar X-1.796 \times {\frac{s}{\sqrt{n} } }$ < $\mu$ < $\bar X+1.796 \times {\frac{s}{\sqrt{n} } }$ ) = 0.90

90% confidence interval for $\mu$ = [ $\bar X-1.796 \times {\frac{s}{\sqrt{n} } }$ , $\bar X+1.796 \times {\frac{s}{\sqrt{n} } }$ ]

= [ $21.88-1.796 \times {\frac{0.201}{\sqrt{12} } }$ , $21.88+1.796 \times {\frac{0.201}{\sqrt{12} } }$ ]

= [21.78, 21.98]

Therefore, a 90% confidence interval for the mean weight is [21.78 ounces, 21.98 ounces].

8 0

3 years ago

1. 15 is what percent of 40? 2. 15 is 30% of what number? 3. What number is 120% of 70?

Elis [28]

1. 15 is what percent of 40?
15 * 100 / 40 = 37.5
answer is 15 is 37.5% of 40

2. 15 is 30% of what number?
15 / 0.3 = 50
answer : 15 is 30% of 50

3. What number is 120% of 70?
120% = 1.2
1.2 + 1 = 2.2

2.2 * 70 = 154
answer: 154 is 120% of 70?

5 0

3 years ago

Which of the following ratios will form a proportion with 2/3. a) 9/12 b) 6/15 c) 12/18 d) 6/8

Brums [2.3K]

The answer is c, 12/18.

4 0

3 years ago

Hiiii Can someone please help me please

Ede4ka [16]

Answer:

B, H

Step-by-step explanation:

The electrician charges 45 dollars per hour and 30 at the beginning. We are multiplying the hours, h, by 45 to get 45h. We add 30 to get C=45h+30

Jerome will always earn 75 dollars, but he also gets 10 percent commission, which is 0.10.

6 0

3 years ago

Read 2 more answers