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GenaCL600 [577]
3 years ago
8

Matias solved 28 math problems in 20 minutes yesterday. Using the same rate, how many math problems can Matias solve in 90 minut

es?
Mathematics
2 answers:
Ivahew [28]3 years ago
4 0

Answer:

A handy technique I like to use for these type of problems is Dimensional Analysis.

Basically the way it works is you create conversion factors between units and multiply and cancel out units.

You start by setting up an equality.

In this case the equality is 28 math problems = 20 minutes.

To get a conversion factor from this equation, you have to move all terms onto one side so that the other side is 1.

To do this, you divide both sides by 20 minutes.

This leaves you with:

28 math problems / 20 minutes = 20 minutes / 20 minutes

On the right side, you can see that 20 minutes / 20 minutes is just equal to one. And on the left side you separate the numbers and units to get 28/20 math problems/ minute.

28/20 is equal to 1.4 and math problems / minute can be interpreted as math problems per minute.

So we now know that Matias can do 1.4 math problems/min or 1.4 math problems per minute.

To find how many math problems he can do in 90 minutes you have to multiply the conversion factor(1.4) by the number of minutes (90) so that the minutes cancel out and you are left with math problems.

so:

90 minutes * 1.4 math problems / minutes = 90*1.4 math problems * minutes / minutes

minutes/minutes is just equal to one, so the answer is 126 math problems.

Hope that helped :)

kherson [118]3 years ago
3 0

Answer:

she can solve 84 math problems in 90 minutes, because 20 minutes x 3 = 90 minutes. so 28 x 3 = 84

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Please ASAP help please !!! Help me anyone
worty [1.4K]

difference of squares means that both the terms are square terms. (also there must be a - symbol)

for example

y^2 - 4

square root of y^2 is y

square root of 4 is +2 as well as -2

so you would factorise it like this:

(y+2)(y-2)

1. y^4 has a square root of y^2 as y^2 × y^2 is y^4.

<em>h</em><em>o</em><em>w</em><em>e</em><em>v</em><em>e</em><em>r</em><em>,</em><em> </em>-2 doesnt have a whole number square root so it is not a difference of squares.

2. 25 has a square root of 5. m^2 has a square root of m. n^4 has a square root of n^2. so this 25m^2n^4 is a square term.

1 has a square root of +1 and -1.

therefore, this one is a difference of squares. <u>(</u><u>5</u><u>m</u><u>n</u><u>^</u><u>2</u><u> </u><u>+</u><u>1</u><u>)</u><u> </u><u>(</u><u>5</u><u>mn^2</u><u> </u><u>-</u><u>1</u><u>)</u>

3. p^8 has a square root of p^4. q^4 has a square root of +q^2 and -q^2)

so it is a difference of squares. <u>(</u><u>p</u><u>^</u><u>4</u><u>+</u><u>q</u><u>^</u><u>2</u><u>)</u><u>(</u><u>p</u><u>^</u><u>4</u><u> </u><u>-</u><u>q</u><u>^</u><u>2</u><u>)</u>

4. 16x^2 is a square term as irs square root is 4x.

<em>h</em><em>o</em><em>w</em><em>e</em><em>v</em><em>e</em><em>r</em><em>,</em><em> </em>24 is not a square term.

therefore, it is not a difference of squares.

6 0
3 years ago
(3x - 2)³= <br>gives the solution pls.​
Nonamiya [84]

Answer:

27x^3 - 54x^2 + 36x - 8

Step-by-step explanation:

(3x - 2)^3

= (3x - 2) (3x - 2) (3x - 2)

= 27x^3 - 54x^2 + 36x - 8

Hope this helps :)

Let me know if there are any mistakes!!

5 0
3 years ago
Read 2 more answers
If x = - 4 , the value of y = - 6x
Klio2033 [76]

Answer:

y = 24

Step-by-step explanation:

Step 1:

y = - 6x        Equation

Step 2:

x = - 4        Given

Step 3:

y = - 6 ( - 4 )        Input x value

Answer:

y = 24

Hope This Helps :)

4 0
3 years ago
A business was valued at £80000 at the start of 2013. In 5 years the value of this business raised to £95000. this is equivalent
Yuri [45]

the yearly increase of x% assumes is compounding yearly, so let's use that.

~~~~~~ \textit{Compound Interest Earned Amount} \\\\ A=P\left(1+\frac{r}{n}\right)^{nt} \quad \begin{cases} A=\textit{accumulated amount}\dotfill &\£95000\\ P=\textit{original amount deposited}\dotfill &\£80000\\ r=rate\to r\%\to \frac{r}{100}\\ n= \begin{array}{llll} \textit{times it compounds per year}\\ \textit{yearly, thus once} \end{array}\dotfill &1\\ t=years\dotfill &5 \end{cases}

95000=80000\left(1+\frac{~~ \frac{r}{100}~~}{1}\right)^{1\cdot 5}\implies \cfrac{95000}{80000}=\left( 1+\cfrac{r}{100} \right)^5 \\\\\\ \cfrac{19}{16}=\left( 1+\cfrac{r}{100} \right)^5\implies \sqrt[5]{\cfrac{19}{16}}=1+\cfrac{r}{100}\implies \sqrt[5]{\cfrac{19}{16}}=\cfrac{100+r}{100} \\\\\\ 100\sqrt[5]{\cfrac{19}{16}}=100+r\implies 100\sqrt[5]{\cfrac{19}{16}}-100=r\implies 3.5\approx r

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2 years ago
Y+9-x; use x=1, and y=3
borishaifa [10]

Answer:

13

Step-by-step explanation:

because 3+9=12+1=13

7 0
3 years ago
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