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3 years ago

15

At birth, the rhino weighed 85 pounds. The rhino gained the same amount of pounds each month for 6 months. After 6 months, the r

hino weighed 493 pounds. How much weight did it gain each month?

1 answer:

Arada [10]3 years ago

5 0

Answer:

68 pounds a month

Step-by-step explanation:

so what i did is subtract 85 because that was the starting weight, now we have 408 I divided 6 (how many months) and got 68.

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I WILL MARK BRAINLIEST Twelve is added to a number and then the sum is multiplied by 4/5 to give 23.6. What is the number?

Aliun [14]

Answer: 17.5 or 35/2

Step-by-step explanation:

(If you change 4/5 to a decimal, it makes this easier. 4/5 would be 0.8.)

23.6 = (12 + x)*0.8

23.6 = 9.6 + 0.8x

14 = 0.8x

17.5 = x

17.5 as an improper fraction would be 35/2.

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3 years ago

The product of two numbers is 41. One of the numbers

shepuryov [24]

<h3>Answer: 5 - 4i (choice A)</h3>

===================================================

Work Shown:

x = the other number

(5+4i)*x = 41

x = 41/(5+4i)

x = 41*(5-4i)/( (5+4i)*(5-4i) ) ..... see note below

x = 41*(5-4i)/( 41 )

x = (41/41)*(5-4i)

x = 5 - 4i

As a way to check, (5+4i)*(5-4i) = 5^2+4^2 = 25+16 = 41

The rule used is (a-bi)(a+bi) = a^2 + b^2

-----------

Note: I multiplied top and bottom by (5-4i) to get rid of the imaginary term in the denominator.

3 0

3 years ago

A chemical substance has a decay rate of 6.9% per day. The rate of change of an amount N of the chemical is given by the equatio

GaryK [48]

Answer:

a) $N=N_0e^{-0.069t}$

b) $N=696.9$ grams

c) $t=10$ days

Step-by-step explanation:

a)

We are going to use separation of variables to solve.

Get all your t's to one side and your N's to opposing side.

$\frac{dN}{dt}=-0.069N$

Multiply both sides by $dt$ :

$dN=-0.069N dt$

Divided both sides by $N$ :

$\frac{dN}{N}=-0.069 dt$

Integrate both sides:

$\ln|N|=-0.069t+C$

The equivalent exponential form is:

$e^{-0.069t+C}=N$

Using law of exponents you can write this as:

$e^{-0.069t}e^C=N$

$e^C$ is just a positive constant that I'm going to replace with K:

$e^{-0.069t}K=N$

Applying the symmetric property of equality:

$N=e^{-0.069t}K$

Applying the commutative property of multiplication:

$N=Ke^{-0.069t}$

K actually represents the initial amount of chemical substance since when plugging in 0 for t you get K for N, like so:

$N=Ke^{-0.069 \cdot 0}$

$N=Ke^{0}$

$N=K(1)$

$N=K$

We are given at time 0 the amount of chemical substance,N, is K. They want us to represent this value with $N_0$ instead. So the exponential equation is:

$N=N_0e^{-0.069t}$

b)

We are given $N_0=800$ at $t=0$ .

We are asked to find how much of the chemical substance, N, remains after 2 days. So we replace t with 2 in $N=800e^{-0.069t}$ :

$N=800e^{-0.069 \cdot 2}$

Put into calculator:

$N=696.9$ (this was rounded to the nearest tenths)

c)

The last part is asking for how many days will it take a initial 800 grams to go down to half of 800 grams.

We need to see the following equation:

$\frac{1}{2}(800)=800e^{-0.069t}$

$400=800e^{-0.069t}$

Divide both sides by 800:

$\frac{400}{800}=e^{-0.069t}$

Reduce the fraction:

$\frac{1}{2}=e^{-0.069t}$

Convert to logarithmic form:

$\ln(\frac{1}{2})=-0.069t$

Divide both sides by -0.069:

$\frac{\ln(\frac{1}{2})}{-0.069}=t$

Input into calculator:

$10.0=t$

$t=10.0$

$t=10$

6 0

3 years ago

Please help with this!! Triangles and angles

Delvig [45]

Answer:

Hello, for the second question, you can actually form a triangle from the line. From there, you can see the height (aka y) will be easier to solve. I hope this helps!

Ans: 1) 47.5

2) 3.4

Step-by-step explanation:

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3 years ago

The are of a rectangular city park is 25/54 square miles. The length of the park is 5/9 mile. What is the with, in miles, of the

Afina-wow [57]

A=L•W
25/49=5/9•W

25/49=5/9•W
/ 5/9. / 5/9. (Divided by 5/9)

Answer- about .918 miles

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4 years ago