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3 years ago

Kevin is 3 times as old as Daniel. 4 years ago, Kevin was 5 times as old as Daniel.

1 answer:

8 0

X is Kevin; Y is Dan

X = 3Y

X - 4 = 5(Y - 4)

3Y - 4 = 5(Y - 4)
3Y - 4 = 5Y - 20
   + 4 +4
4 cancels each other out.
3Y = 5Y - 16
   - 5 -5
5 cancels each other out.
-2Y = -16
/2 /2
   Y = 8

X = 3Y;
X = 3 x 8;

Thus,
X = 24;
Kevin(x) is 24

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When eight times an unknown number is decreased by 208 the result is four times the unknown number.

Naddika [18.5K]

I think

This is your typical algebra question where you are looking for an unknown value given some information. The information can be set up as:
8 - x = 4*(x +3)

Distribute the 4:
8 - x = 4x + 12

Rearrange to get variables on one side:
8 - 12 = 4x + x

Simplifiy:
-4 = 5x

Isolate the variable:
-4/5 = x

6 0

3 years ago

Two years ago Juanita bought 2 shirts for $15 and last year she bought 4 shirts for $45. Assuming the prices will increase linea

AleksandrR [38]

Answer:

This year, Juanita will have to use $75.

Step-by-step explanation:

Because if 2 shirts is $15, 4 shirts will be $30. $45 is $15 more than $30, so the increase is $15. 2*4 is 8, so that will make it 15*4=60. 60+15=75.

8 0

3 years ago

How many solutions for linear equation 3x + 5y = 25 can be found so that −20 < y < 10, and x is an integer?

ch4aika [34]

Answer:

Step-by-step explanation:

3x = 25 - 5y

-100 < 5y < 50

-50 < -5y < 100

-25 < 25 - 5y < 125

-8.333 < x < 41.667

41+8+1 = 50

5 0

3 years ago

What is the completely simplified equivalent of 2/(5+i)?

Bezzdna [24]

namely, let's rationalize the denominator in the fraction, for which case we'll be using the <u>conjugate</u> of that denominator, so we'll multiply top and bottom by its <u>conjugate</u>.

so the denominator is 5 + i, simply enough, its conjugate is just 5 - i, recall that same/same = 1, thus (5-i)/(5-i) = 1, and any expression multiplied by 1 is just itself, so we're not really changing the fraction per se.

$\bf \cfrac{2}{5+i}\cdot \cfrac{5-i}{5-i}\implies \cfrac{2(5-i)}{\stackrel{\textit{difference of squares}}{(5+i)(5-i)}}\implies \cfrac{2(5-i)}{\stackrel{\textit{recall }i^2=-1}{5^2-i^2}}\implies \cfrac{2(5-i)}{25-(-1)} \\\\\\ \cfrac{2(5-i)}{25+1}\implies \cfrac{2(5-i)}{26}\implies \cfrac{5-i}{13}$

4 0

3 years ago

The surface areas of two similar solids are 340 yd² and 1,158 yd². The volume of the larger solid is 1,712 yd³. What is the volu

ratelena [41]

The ratio of surface area is equal to the ratio of the square of the corresponding dimensions. And ratio of volumes of two solids is equal to the cube of the ratio of the corresponding dimensions .

We start with the relation between ratio of surface area and ratio of corresponding sides. That is

$\frac{340}{1158}=(\frac{x}{y} )^2$

Here x and y are the corresponding sides .

$\frac{x}{y} =\sqrt{\frac{340}{1158} } =0.542$

Let the volume of the smaller one be v

$\frac{v}{1712}=0.542^3$

$v=1712*0.542^3=272$

So for the smaller solid, volume is 272 . And the correct option is the first option .

4 0

3 years ago