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3 years ago

1. An open box is to be made from a sheet of card 40cm by 30cm. A square of side x cm is to be

Mathematics

1 answer:

tino4ka555 [31]3 years ago

3 0

Step-by-step explanation:

AB = DC = 40 - 2x

AD = BC = 30 - 2x

there is not more explanation possible, I think.

we cut off from each side 2 pieces of x cm. so, AB, DC, AD, BC are the the remaining lengths.

the volume of the box is ground area times height (x is the length of the remaining flaps after the cut, so, when folding up these flaps/sides, they will be x cm high).

Volume = y = AB×AD×x

=> y = (40-2x)×(30-2x)×x = (1200 - 60x - 80x + 4x²)×x =

= (1200 - 140x + 4x²)×x = 4x³ - 140x² + 1200x

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Solve for x.<br> 144°<br> 18 degrees<br> 30 degrees<br> 48 degrees<br> 120 degrees

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Step-by-step explanation:

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3 years ago

Kati brought 1/4 dozen doughnuts to school. How many doughnuts did Kati bring

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3 years ago

A random sample of 10 shipments of stick-on labels showed the following order sizes.10,520 56,910 52,454 17,902 25,914 56,607 21

sammy [17]

Answer:

Confidence Interval: (21596,46428)

Step-by-step explanation:

We are given the following data set:

10520, 56910, 52454, 17902, 25914, 56607, 21861, 25039, 25983, 46929

Formula:

$\text{Standard Deviation} = \sqrt{\displaystyle\frac{\sum (x_i -\bar{x})^2}{n-1}}$

where $x_i$ are data points, $\bar{x}$ is the mean and n is the number of observations.

$Mean = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}$

$Mean =\displaystyle\frac{340119}{10} = 34011.9$

Sum of squares of differences = 551869365.6 + 524322983.6 + 340111052.4 + 259528878 + 65575984.41 + 510538544 + 147644370.8 + 80512934.41 + 64463235.21 + 166851472.4 = 2711418821

$S.D = \sqrt{\frac{2711418821}{9}} = 17357.09$

Confidence interval:

$\mu \pm t_{critical}\frac{\sigma}{\sqrt{n}}$

Putting the values, we get,

$t_{critical}\text{ at degree of freedom 9 and}~\alpha_{0.05} = \pm 2.2621$

$34011.9 \pm 2.2621(\frac{17357.09}{\sqrt{10}} ) = 34011.9 \pm 12416.20 = (21595.7,46428.1) \approx (21596,46428)$

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3 years ago