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4 years ago

If 40% of a number is 80 what is 25% of that number?

Mathematics

1 answer:

olga2289 [7]4 years ago

7 0

Answer:

25% of 200 is 50

Step-by-step explanation

40% of a number is 80

.40 * n = 80

Divide each side by .4

.40 n/.4 = 80/.4

n = 200

The number is 200

Now lets find 25 percent of that number

.25 * 200 = 50

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The sum of 9 and a number is less than 12. Which of the following

Fofino [41]

Answer:

9+x<12

Step-by-step explanation:

add 9 to an unknown number.

9+x

use the < less than symbol (instead of an equal sign) and write 12.

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3 years ago

Read 2 more answers

A rancher wishes to build a fence to enclose a 2250 square yard rectangular field. Along one side the fence is to be made of hea

Bess [88]

Answer:

The least cost of fencing for the rancher is $1200

Step-by-step explanation:

Let x be the width and y the length of the rectangular field.

Let C the total cost of the rectangular field.

The side made of heavy duty material of length of x costs 16 dollars a yard. The three sides not made of heavy duty material cost $4 per yard, their side lengths are x, y, y. Thus

$C=4x+4y+4y+16x\\C=20x+8y$

We know that the total area of rectangular field should be 2250 square yards,

$x\cdot y=2250$

We can say that $y=\frac{2250}{x}$

Substituting into the total cost of the rectangular field, we get

$C=20x+8(\frac{2250}{x})\\\\C=20x+\frac{18000}{x}$

We have to figure out where the function is increasing and decreasing. Differentiating,

$\frac{d}{dx}C=\frac{d}{dx}\left(20x+\frac{18000}{x}\right)\\\\C'=20-\frac{18000}{x^2}$

Next, we find the critical points of the derivative

$20-\frac{18000}{x^2}=0\\\\20x^2-\frac{18000}{x^2}x^2=0\cdot \:x^2\\\\20x^2-18000=0\\\\20x^2-18000+18000=0+18000\\\\20x^2=18000\\\\\frac{20x^2}{20}=\frac{18000}{20}\\\\x^2=900\\\\\mathrm{For\:}x^2=f\left(a\right)\mathrm{\:the\:solutions\:are\:}x=\sqrt{f\left(a\right)},\:\:-\sqrt{f\left(a\right)}\\\\x=\sqrt{900},\:x=-\sqrt{900}\\\\x=30,\:x=-30$

Because the length is always positive the only point we take is $x=30$ . We thus test the intervals $(0, 30)$ and $(30, \infty)$

$C'(20)=20-\frac{18000}{20^2} = -25 < 0\\\\C'(40)= 20-\frac{18000}{20^2} = 8.75 >0$

we see that total cost function is decreasing on $(0, 30)$ and increasing on $(30, \infty)$ . Therefore, the minimum is attained at $x=30$ , so the minimal cost is

$C(30)=20(30)+\frac{18000}{30}\\C(30)=1200$

The least cost of fencing for the rancher is $1200

Here’s the diagram:

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3 years ago

<img src="https://tex.z-dn.net/?f=%5Csqrt%7Bx%7D%20%2B1%3D3%5C%5C" id="TexFormula1" title="\sqrt{x} +1=3\\" alt="\sqrt{x} +1=3\\

Eduardwww [97]

Answer:

x = 4

Step-by-step explanation:

√x + 1 = 3

√x = 3 - 1

√x = 2

(√x)² = (2)²

x = 4

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3 years ago

A train leaves little? rock, arkansas, and travels north at 80 kilometers per hour. another train leaves at the same time and tr

balandron [24]

p(80+60)=560

p(140)=560

560/140 = 4 hours

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3 years ago

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STALIN [3.7K]

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3 years ago