All Answers 356076 Answers

910 windows, cuz 910 +

That would be hard to know since an average of 8 living things or organisms is being born every second and an average of 5 organisms are dying every second. 

I know this joke. The answer is "21" for the joke, but its actually 19.

There are two different ways to multiply fractions

a) Multiply as is

b) convert into decimals and then multiply

To do a) you first write down 40/47 x 3/10, then you multiply 40 x 3 and 47 x 10. After multiplying you get 120/470, but this not simplified. To simplify, divide 120 by 10 and 470 by 10. The answer is 12/47.

yes he did he said 5 and 3over 5

Too many!

The percentage decrease is given by :

( [ Old Price  - New Price] / [ Old Price]   * 100 ) %      ....so we have......

( [140 - 119] / [ 140] *100 ) %  =

( [21/ 140] * 100) %  =

(2100 / 140) % =

(210 / 14) %  =

15 %

The nth term  is given by :

0.2 (1/2)^{(n -1)}     so, when n = 7.......the 7th term  =

0.2 (1/2) ^{(7 -1)}  =

0.2 (1/2) ⁶  =

0.003125

 (7x+3)/(2)+(x+6)/(4)=18     multiply through by the common denominator of 2 and 4, i.e., 4

(7x + 3)(2)  + (x + 6)   = 72        distribute the 2 over the terms in the parentheses

14x + 6  + x + 6   = 72       simplify

15x + 12   = 72      subtract 12 from both sides

15x   = 60      divide both sides by 15

x = 4

Try 824-100 and see what u get.

2225.5

V_cylinder = pi*r²*h

V_cone = pi*R²*h/3

V_cylinder = V_cone  ⇒  r² = R²/3  so  R = sqrt(3)*r

.

Hi Robert, 

There are probably elements of your question that were not explained - like how long can a drilled hole be but this is my answer based on the information given and my understanig of the problem :)

Hello

Please excuse the possibly simple arithmetic question.

A friend has asked me to make him a croquet mallet head and has supplied me with an aluminium block measuring 280mm X 50mm X 50mm.  

Volume = 280*50*50 = 280*50*50 = 700,000mm^3

This block weighs 1850gm.

I need to reduce the weight to 1333gm.

Need to make holes to remove 1850-1333=  517grams

517/1850*700000 = 195621.6216216216216216

Need to remove 195,622mm^3

To do this I intend to drill a number of holes through the block from side to side.

I must drill an equal number of holes on each end of the mallet so that it is balanced.

I am comfortable working with with wood but aluminium is new to me and I don't want to muck it up.

I have a set of drills of the size (Murphy was an optimist) 9/16", 5/8', 11/16", 3/4", 13/16", 7/8", 15/16" and 1".

I also have a 2 full sets of both metric and inch drills up to 13mm and 1/2" respectively

The biggest diameter that you mentioned was 13mm So I will use that one.

The dimensions given are in mm so I am not even going to consider the imperial bits.

2pi*6.5^2*x=195,622

x=195622/(2*pi*6.5^2) = 736.9043379295325296

The block is only 280mm deep so

736.9/140 = 5.2635714285714286

122.8166666666666667 = 122.8166666666666667

6 holes on each side, each one has 13mm diameter and 122.82cm length

Check

6*2*pi*6.5^2*122.82 = 195626mm^3

195626-195622 = 4

So it is out by 4mm^3 which is negligable.

You have a volume of 50 x 50 x 280 mm  =  700000 cubic mm

The mass is                                                    1850 gm

You want to reduce the mass by ,drilling holes,to 1333 gm.

So you need to reduce the volume to (1333/1850) x 700000 cubic mm

which is a volume of                                                   504378.378  cubic mm

Subtract  the new volume from the old one to see how much you need to cut away

that is    700000  - 504378.378  = 195621.621 cubic mm

You didn't say whether you would drill lengthways or sideways thru the block,but either way,the volume of each hole you drill is just  (pi)(r^2)   x  length of hole,where r is the radius of the hole,that is the radius of your drill. (Make sure it's the radius,and not the diameter,or you will be removing more.)

Happy drilling!

when 3a squared b - 2ab+4ba squared- 6a5ba is simplifed

Is this what you mean?

\(3a^2 b - 2ab+4ba^2- 6a5ba\\ =3a^2 b - 2ab+4ba^2- 30ba^2\\ =3a^2 b - 2ab+4a^2b- 30a^2b\\ =3a^2 b +4a^2b- 30a^2b \quad - 2ab\\ =(3+4-30)a^2b \quad - 2ab\\ =-23a^2b \quad - 2ab\\\)

You mean decimal notation to standard form ?         (standard form is what the British call scientific notation)

0.000456 = 4.56e-4        

I just did that by entering it into the web 2.0 calculator

If you want to do it by hand here is a video that explains it.

if i went to sleep at 8:58 pm and woke up at 11:50 am, for how long did i sleep?

8:58 to 9:00   is                            2 minutes

9pm to midnight is        3 hours

midnight ot 11 am is   11 hours

11:00 to 11:50 is                           50 minutes

------------------------------------------------------------

Total =                         14 hours   52 minutes

How do u put tan inverse? I need help.

arc tan is the same as inverse tan so you can just type in  

atan( number) and press equals.

Or 

you can press

[2nd] [atan] number =

Make sure the calc is set to degrees or radians as needed.  There are 2 buttosn on the bottoe left of the calc to set this. :)

Y=X(30.100)+50(X(X-1)/2)

Y=100(30.100)+50(100x99/2)

Y= ?

100(30.100)+50(100x99/2) = 250510

I just did this on the forum calculator.  :))

1.94*10^-67

Thank you  CPhill

The sum of the roots of a quadratic  =  -b/a

So ........

[3 + √5[  + [3 - √5]  = -b/a

6  =  -b/-2    →    b = 12

And the product of the roots of a quadratic =  c / a.....so we have that

[3 + √5] [ 3 - √5]  =  c / -2

[9 - 5]   = c /-2

4  = c / -2  

c = -8

So......our quadratic is....

y = -2x^2 + 12x - 8

And the x  coordinate of the vertex =   -b/2a   =  -12/ [2(-2)] = 12/4 = 3

And the y coordinate is  .......

-2(3)^2 + 12(3) -  8

-2(9) + 36 - 8

-18 + 36 - 8

10

So....rhe vertex is  (3, 10)

Here's the graph : https://www.desmos.com/calculator/aqwwi79n10

Let $b$ and $c$ be constants such that the quadratic \(-2x^2 +bx +c\) has roots \(3+\sqrt{5}\) and \(3-\sqrt{5}\). Find the vertex of the graph of the equation \(y=-2x^2 + bx + c\).

5