Math Problems!........share It Here!

[Tank Girl]

The circumference of

a circle is 2 pi (about 6.28) times the radius of the circle.

Therefore the radius is the circumference divided by 6.28:

 

C = 2*pi*R

 

C/(2*pi) = R

[Tank Girl]

The circumference of

a circle is 2 pi (about 6.28) times the radius of the circle.

Therefore the radius is the circumference divided by 6.28:

 

C = 2*pi*R

 

C/(2*pi) = R

[Tank Girl]

okay ive read the post earlier and how is it derived, i hope i can explain in simpler terms, math is such an intricate subject to discuss ( i love math!) first of all i have to discuss where it came from.. the CIRCLE, thats where it came from

 

Circle, in geometry, a two-dimensional curve such that each point on the curve is the same distance from a fixed point, called the center. The term circle may also be applied to the region enclosed by this curve. Simply said!

 

The circumference—distance around the edge—of a circle is equal to a constant, pi (symbol p), times the circle’s diameter: C = pd. Since the diameter of a circle is equal to twice the circle’s radius, the circumference also equals two times pi times the radius: C = 2pr. Pi is one of the most important mathematical constants, and plays a role in many calculations and proofs in mathematics, physics, engineering, and other sciences. The first ten digits of pi are 3.141592654, although the approximations 3.14 or 3 are sufficiently accurate for many calculations. 3. 14 and the common symbol, dont they teach these things in 6th grade?

 

Of all two-dimensional figures having the same perimeter, the circle has the greatest area. The area of a circle is equal to pi multiplied by the square of the circle’s radius: A = pr2.

 

To answer your question clearly i hope i answer it well is that this formula is derived from the Babylonians. Am i correct? Teehee! well someone has to give another math problem na!!!

[destron]

Great answers up there. ^^^

 

OK more of Math problems.

 

Sabong problem (again) :upside:

One day Quin went to 5 cockpit arenas. Each arena has an entrance fee of 5pesos and a winning bet gets 5 times the money bet. Everytime Quin entered an arena he plays only once, bets all his money, and wins. Also he gives a 5peso tip to the guard of the arena he just played. At the end of the day, he has 555 pesos.

 

How much money did he originally have?

Answer needs to be accurate in decimal places.

[ibirp]

orignal nomey = 7.6752

 

formula will be [(x-5) *5]-5 ---> reads as x (current money) minus 5 (entrace fee) then multiply the result to 5 (price you win) then subtract 5 from the result (tip to the guard).

 

so:

 

7.6752 - 5 = 2.6752; * 5 = 13.376; - 5 = 8.376 (first arena)

8,376 - 5 = 3.376; * 5 = 16.88; -5 = 11.88 (2nd arena)

11.88 - 5 = 6.88; * 5 = 34.4; -5 = 29.4 (3rd arena)

29.4 - 5 = 24.4; * 5 = 122; -5 = 117 (4th arena)

117 - 5 = 112 * 5 = 560; - 5 = 555 (5th arena)

 

this is actually done using manual steps (i worked backwards from 555 + 5 = 560; /5 = 112; + 5 = 117, and so on...), i'm still working for a formula for this...

[destron]

Preciseness!! ^^

 

And you are right on track for my next question; which is the fomula..

[mark_pogi]

prove that:

 

11 + 2 = 1

 

[destron]

Gee this is not moving.

 

A quick question:

How much dirt is in a hole that is 3 meters deep and 6 inches in diameter?

[stankyou]

Gee this is not moving.

 

A quick question:

How much dirt is in a hole that is 3 meters deep and 6 inches in diameter?

 

volume = Area * Height = 3337.78 cubic inches

 

tama ba?

[destron]

volume = Area * Height = 3337.78 cubic inches

 

tama ba?

 

Nope. Try again.

 

Q:How much dirt is in a hole that is 3 meters deep and 6 inches in diameter?

[stankyou]

Nope. Try again.

 

Q:How much dirt is in a hole that is 3 meters deep and 6 inches in diameter?

 

 

hmmm... *gets a piece of paper and recalculates*

 

anong unit mo ba to kelangan? metric or english system?

Edited November 26, 2007 by stankyou

[destron]

hmmm... *gets a piece of paper and recalculates*

 

anong unit mo ba to kelangan? metric or english system?

 

Metric or English will do.

[lomex32]

6 in * 2.54 cm/in = 15.24cm

Depth 3m * 100cm/m = 300 cm

 

Volume = 3.1416 x 15.24 cm x 15.24 cm x 300 cm

= 218898.14 cubic cm

 

 

Nope. Try again.

 

Q:How much dirt is in a hole that is 3 meters deep and 6 inches in diameter?

[bene_factor]

I guess the answer is zero, it being a hole?

 

Unless the question was: How much dirt _was_ in the hole?

 

but that's a good one.

[bubuy]

How many total squares are there in a regulation chess board?

[bubuy]

Can you write the numbers 0 through 10 using five figure 2s, no more and no less, and the usual signs: +, -, x, /, and parentheses? To start:

 

0 = 2 - 2/2 - 2/2

1 = 2 + 2 + 2 - 2 - 2

2 =

3 =

4 =

.

.

.

10 =

[destron]

I guess the answer is zero, it being a hole?

 

Unless the question was: How much dirt _was_ in the hole?

 

but that's a good one.

 

You got it!

 

How many total squares are there in a regulation chess board?

 

There are 65 squares on a chess board. 64 little squares and the whole board is a square so 64+1=65

All possible combinations of different sized squares it comes to 204.

All possible combinations of different sized rectangles it comes to 1296.

 

Can you write the numbers 0 through 10 using five figure 2s, no more and no less, and the usual signs: +, -, x, /, and parentheses? To start:

 

0 = 2 - 2/2 -2/2

1 = 2 -2/2 +2 -2

2 = 2 +2 +2 -2 -2

3 = 2 +2/2 +2 -2

4 = 2 +2/2 +2/2

5 = 2 +2 +2 -2/2

6 = 2 +2 +2 +2 -2

7 = 2 +2 +2 +2/2

8 = 2 x2 x2 +2 -2

9 = 2 x2 x2 +2/2

10 = 2 +2 +2 +2 +2

[destron]

If a=b,

 

multiplying both sides by a,

a²=ab

 

subtracting b² from both sides,

a²-b²=ab-b²

 

factoring both sides,

(a+b )(a-b )=b(a-b )

 

dividing both sides by a-b,

a+b=b

 

but since a=b,

b+b=b

 

2b=b

 

dividing both sides by b,

2=1

 

Q: Where did it went wrong?

[twisted minds]

If a=b,

 

multiplying both sides by a,

a²=ab

 

subtracting b² from both sides,

a²-b²=ab-b²

 

factoring both sides,

(a+b )(a-b )=b(a-b )

 

dividing both sides by a-b,

a+b=b

 

but since a=b,

b+b=b

 

2b=b

 

dividing both sides by b,

2=1

 

Q: Where did it went wrong?

 

if a=b then a-b = 0. so in step 4, you are dividing both sides by 0.

[dfgvan]

eto para sa inyo

 

sagutin nyo ha

pwedeng magdiscuss

isa ito sa mga problems nabinibigay ko sa mga students ko

 

si A bumaba sa escalator tumakbo nabilang nya 75 steps ang hinakbang nya

si B bumaba sa escalator naglakad nabilang nya 50 steps ang hinakbang nya

ang pagtakbo ni A is twice as fast sa paglakad ni B

 

ilan lahat ang steps ng escalator

[twisted minds]

eto para sa inyo

 

sagutin nyo ha

pwedeng magdiscuss

isa ito sa mga problems nabinibigay ko sa mga students ko

 

si A bumaba sa escalator tumakbo nabilang nya 75 steps ang hinakbang nya

si B bumaba sa escalator naglakad nabilang nya 50 steps ang hinakbang nya

ang pagtakbo ni A is twice as fast sa paglakad ni B

 

ilan lahat ang steps ng escalator

 

hehe ... tricky ... A must be gong down the escalator going up ... and B must going down the escalator going down ... but still there are steps hidden inside so i really would not know how to calculate this

[dfgvan]

hehe ... tricky ... A must be gong down the escalator going up ... and B must going down the escalator going down ... but still there are steps hidden inside so i really would not know how to calculate this

 

 

actually it isn't

1. assume X to be the rate at which a step disappears. this will be constant as this will be the rate of the escalator

2. they both went down using the same escalator which was going down.

3. A = rate of A. B = rate of B.

 

V=D/T

both traveled the same distance

D is constant

 

 

answer 100 steps

[The_Blade]

Great answers up there. ^^^

 

OK more of Math problems.

 

Sabong problem (again) :upside:

One day Quin went to 5 cockpit arenas. Each arena has an entrance fee of 5pesos and a winning bet gets 5 times the money bet. Everytime Quin entered an arena he plays only once, bets all his money, and wins. Also he gives a 5peso tip to the guard of the arena he just played. At the end of the day, he has 555 pesos.

 

How much money did he originally have?

Answer needs to be accurate in decimal places.

 

 

orignal nomey = 7.6752

 

 

 

 

formula will be [(x-5) *5]-5 ---> reads as x (current money) minus 5 (entrace fee) then multiply the result to 5 (price you win) then subtract 5 from the result (tip to the guard).

 

so:

 

7.6752 - 5 = 2.6752; * 5 = 13.376; - 5 = 8.376 (first arena)

8,376 - 5 = 3.376; * 5 = 16.88; -5 = 11.88 (2nd arena)

11.88 - 5 = 6.88; * 5 = 34.4; -5 = 29.4 (3rd arena)

29.4 - 5 = 24.4; * 5 = 122; -5 = 117 (4th arena)

117 - 5 = 112 * 5 = 560; - 5 = 555 (5th arena)

 

this is actually done using manual steps (i worked backwards from 555 + 5 = 560; /5 = 112; + 5 = 117, and so on...), i'm still working for a formula for this...

 

 

 

let X0 be the original money.

let X5 the money on hand after the 5th arena =555

 

working the eqaution:

 

the money before the 5th arena is X4

 

(x4 - 5) * 5 - 5 =x5

5x4- 25-5 = x5=555

x4=x5/5 +30/5

x4= 555/5 + 30/5 = 117

 

x3 = x4/5 +30/5

 

working this out and expanding

 

we have

 

 

x0 = (x5+30)/5^5 + (30/ 5^4) +(30/5^3) +(30/5^2) + (30/5^1)

 

in general from the equation would be: where n=5

 

Xn-n = (xn+30)/5^n + (30/ 5^n-1) +(30/5^n-2) +(30/5^n-3) + (30/5^n-4)

 

 

proof:

x0 = (x5+30)/5^5 + (30/ 5^4) +(30/5^3) +(30/5^2) + (30/5^1)

 

X0 = 0.1872 +0.048+ 0.24+1.2+ 6= 7.6752

[destron]

Q1:

Two guys played checkers. They played 5 times. How is it possible that each of them won three games?

 

Q2:

How many times can you subtract 5 from 25?

[skitz]

Two guys played checkers. They played 5 times. How is it possible that each of them won three games?

 

Not specified wether they played against each other. It is possible that each guy won 5 games.

 

How many times can you subtract 5 from 25?

 

Infinite times. Question not limited to non-negative numbers. Another possible answer is ONE. After you subtract 5 from 25 one time, you can not subtract 5 from 25 anymore, you would be subtracting 5 from 20, then 5 from 15, etc.

Edited March 10, 2008 by skitz