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3 years ago

Sita Rahim drove due north for 3 hours at 46 miles per hour. From the

Mathematics

1 answer:

Phantasy [73]3 years ago

6 0

Answer:

224 miles

Step-by-step explanation:

What you would do is take the 3 hours times the 46 mph to get 138 miles.

3*46=138

Next, multiply the 2 hours by the 43 mph to get 86 miles.

2*43=86

Lastly, you're going to add the two.

138+86=224 miles.

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Define a variable and write an inequality to model each situation. A light bulb can be no more than 75 watts to be safely used i

DaniilM [7]

Let the number of watts =w ‘no more than’ means less than or equal to, thus we will use that sign. The inequality can be written as: w<75

3 0

3 years ago

. A theater has 40 rows of seats, where the first row has 27 seats and each subsequent row has

MAXImum [283]

<h3><em>Answer:</em></h3><h3><em></em></h3><h3><em>number of seats in theater = 1035</em></h3><h3><em></em></h3><h3><em>Step-by-step explanation:</em></h3><h3><em></em></h3><h3><em>Given in question as</em></h3><h3><em></em></h3><h3><em>Total number of rows of seat = 30</em></h3><h3><em></em></h3><h3><em>first row contain seat = 20</em></h3><h3><em></em></h3><h3><em>second row contain seat = 21 .. and so on</em></h3><h3><em></em></h3><h3><em>This is in arithmetic progression as 20 , 21 , 22 , 23 ...... so on</em></h3><h3><em></em></h3><h3><em>Then as number of terms N = 30 and first terms = a = 20</em></h3><h3><em></em></h3><h3><em>so we have to find Tn th terms</em></h3><h3><em></em></h3><h3><em>So, Tn th terms = first term + ( N -1 ) × d d= common difference i.e 1</em></h3><h3><em></em></h3><h3><em> Tn th terms = 20 + (30 - 1) × 1</em></h3><h3><em></em></h3><h3><em>Thus, Tn th terms = 49</em></h3><h3><em></em></h3><h3><em>i.e The number of seats in 30th row = 49</em></h3><h3><em></em></h3><h3><em>Now again Total number of seats in theater</em></h3><h3><em></em></h3><h3><em>sum of Nth terms = </em></h3><h3><em></em></h3><h3><em>so = </em></h3><h3><em></em></h3><h3><em> = 15 × 69 = 1035</em></h3><h3><em></em></h3><h3><em>Hence, Total number of seats in theater = 1035 Answer</em></h3>

6 0

3 years ago

Math help please? <3

Tomtit [17]

10m + 80 = P
where every month he gets 10, and for 6 months, he now has 60
plus the 80 he already has
so (10 * 6 ) + 80 = 140

7 0

4 years ago

Read 2 more answers

Sams brother is 7 years older than Sam. His mother is 4 less than 3 times sams age. Their combined age is 63. How old isn’t Sam,

statuscvo [17]

The answer is 14. This is because 63=3+x+3x-4. Then You just subtract it and then you get 64=4x. Then you just divide it and then you get x=16.

4 0

3 years ago

Assume that the helium porosity (in percentage) of coal samples taken from any particular seam is normally distributed with true

IgorLugansk [536]

Answer:

(a) 95% confidence interval for the true average porosity of a certain seam is [4.52 , 5.18].

(b) 98% confidence interval for the true average porosity of a another seam is [4.12 , 4.99].

Step-by-step explanation:

We are given that the helium porosity (in percentage) of coal samples taken from any particular seam is normally distributed with true standard deviation 0.75.

(a) Also, the average porosity for 20 specimens from the seam was 4.85.

Firstly, the pivotal quantity for 95% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\bar X$ = sample average porosity = 4.85

$\sigma$ = population standard deviation = 0.75

n = sample of specimens = 20

$\mu$ = true average porosity

<em>Here for constructing 95% confidence interval we have used One-sample z test statistics as we know about population standard deviation.</em>

<u>So, 95% confidence interval for the true mean, </u> $\mu$ <u> is ;</u>

P(-1.96 < N(0,1) < 1.96) = 0.95 {As the critical value of z at 2.5% level

of significance are -1.96 & 1.96}

P(-1.96 < $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ < 1.96) = 0.95

P( $-1.96 \times {\frac{\sigma}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $1.96 \times {\frac{\sigma}{\sqrt{n} } }$ ) = 0.95

P( $\bar X-1.96 \times {\frac{\sigma}{\sqrt{n} } }$ < $\mu$ < $\bar X+1.96 \times {\frac{\sigma}{\sqrt{n} } }$ ) = 0.95

<u>95% confidence interval for</u> $\mu$ = [ $\bar X-1.96 \times {\frac{\sigma}{\sqrt{n} } }$ , $\bar X+1.96 \times {\frac{\sigma}{\sqrt{n} } }$ ]

= [ $4.85-1.96 \times {\frac{0.75}{\sqrt{20} } }$ , $4.85+1.96 \times {\frac{0.75}{\sqrt{20} } }$ ]

= [4.52 , 5.18]

Therefore, 95% confidence interval for the true average porosity of a certain seam is [4.52 , 5.18].

(b) Now, there is another seam based on 16 specimens with a sample average porosity of 4.56.

The pivotal quantity for 98% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\bar X$ = sample average porosity = 4.56

$\sigma$ = population standard deviation = 0.75

n = sample of specimens = 16

$\mu$ = true average porosity

<em>Here for constructing 98% confidence interval we have used One-sample z test statistics as we know about population standard deviation.</em>

<u>So, 98% confidence interval for the true mean, </u> $\mu$ <u> is ;</u>

P(-2.3263 < N(0,1) < 2.3263) = 0.98 {As the critical value of z at 1% level

of significance are -2.3263 & 2.3263}

P(-2.3263 < $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ < 2.3263) = 0.98

P( $-2.3263 \times {\frac{\sigma}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $2.3263$ ) = 0.98

P( $\bar X-2.3263 \times {\frac{\sigma}{\sqrt{n} } }$ < $\mu$ < $\bar X+2.3263 \times {\frac{\sigma}{\sqrt{n} } }$ ) = 0.98

<u>98% confidence interval for</u> $\mu$ = [ $\bar X-2.3263 \times {\frac{\sigma}{\sqrt{n} } }$ , $\bar X+2.3263 \times {\frac{\sigma}{\sqrt{n} } }$ ]

= [ $4.56-2.3263 \times {\frac{0.75}{\sqrt{16} } }$ , $4.56+2.3263 \times {\frac{0.75}{\sqrt{16} } }$ ]

= [4.12 , 4.99]

Therefore, 98% confidence interval for the true average porosity of a another seam is [4.12 , 4.99].

7 0

3 years ago