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

[cdma]

Try again. 961 is not equal to 960

[gorgonite]

Problem 1. A man has nine children born at regular intervals. The sum of the squares of their ages is equal to the square of the man's age. What are the ages of the children? of the man?

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children are ages 2 to 26, born at 3 year intervals. man is 48 years old.

solution:

 

let a = age of the youngest child

let n = interval between children

let b = age of the father

 

b^2 = a^2 + (a+n)^2 + (a+2n)^2 + ... + (a+8n)^2

 

--> b^2 = a^2 + a^2 + 2an + n^2 + a^2 + 4an + 4n^2 + ... + a^2 + 16an + 64n^2

 

--> b^2 = 9a^2 + 72an + 204n^2

 

if a = 2 and n = 3 then

 

--> b = square_root ( 9(2)^2 + 72(2)(3) + 204(3)^2 )

 

--> b = 48

 

wish i had a more elegant solution

[cdma]

Excellent... Hope you enjoy problem 2 as well.

[hoopburners]

Problem 2. Professor Al Gebra and Professor Cal Culus were chatting. "You know what occurred to me the other day,Cal?"asked Professor Gebra. "What?" said Professor Culus. " When we first met, the square of your age then contained the same three digits as the square of my age, just in a different order", Professor Gebra continued. "You are right. And did you notice that if you take the square of the sum of our ages when we met and split it into two 2-digit numbers, you have my age then and your age now?" remarked Professor Culus.

How old is Professor Gebra now?

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i'm gonna take a shot at this one eventhough i didn't solve this through fomulas, etc. but rather using an excel spreadsheet. prof al gebra's age now is 81 years old while prof cal culus' age now is 72 years old. they first met 47 years ago when prof al gebra was 25 years old while prof cal culus was 16 years old.

 

" When we first met, the square of your age then contained the same three digits as the square of my age, just in a different order", Professor Gebra continued

 

16^2 = 256

25^2 = 625

 

first requirement was met. i assumed prof al gebra's age he was referring to was his age then. he visibly said the age of prof cal culus then but left an open statement on his age when he just said "my age".

 

You are right. And did you notice that if you take the square of the sum of our ages when we met and split it into two 2-digit numbers, you have my age then and your age now?" remarked Professor Culus.

 

(16+25)^2 = 1681

split it into two 2-digit would be = 16 and 81

16 being prof cal culus' age then and

81 being prof al gebra's age now

 

tama po ba?

[cdma]

Excellent hoopburners... I will post some more but i hope others do the same. It is good to do mental exercises too.

[cdma]

Arrange the numerals 1 2 3 4 5 6 7 8 and 9 to form a 9-digit nuber (ABCDEFGHI) whose 2-digit subsets meet the following criteria:

 

AB is divisible by 2

BC is divisible by 3

CD is divisible by 4

DE is divisible by 5

EF is divisible by 6

FG is divisible by 7

GH is divisible by 8

HI is divisible by 9

 

Give at least one of two possible solutions.

[hoopburners]

Arrange the numerals 1 2 3 4 5 6 7 8 and 9 to form a 9-digit nuber (ABCDEFGHI) whose 2-digit subsets meet the following criteria:

 

AB is divisible by 2

BC is divisible by 3

CD is divisible by 4

DE is divisible by 5

EF is divisible by 6

FG is divisible by 7

GH is divisible by 8

HI is divisible by 9

 

Give at least one of two possible solutions.

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7 8 1 2 5 4 9 6 3

A B C D E F G H I

 

AB = 78 / 2 = 39

BC = 81 / 3 = 27

CD = 12 / 4 = 3

DE = 25 / 5 = 5

EF = 54 / 6 = 9

FG = 49 / 7 = 7

GH = 96 / 8 = 12

HI = 63 / 9 = 7

 

i started with letter E since the only number that would be divisible by 5 in the given numbers is 5. from there trial and error na lang po ako

[cdma]

Ang Galing... Let the others find the other solution.

[fastriser]

Kayo po bahala

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hi crystal , nasan ka na?

[rakista_royale]

Hay.., Pasukan na nman, cguro marami magpapa-post ng math problems.., hehehehe...

[gw@p1t0]

hahahahhaha...malamang nga.....

[rich beem]

hehehe... uu nga. ni minsan di pa ako gumamit ng differential equations sa PHP programming.

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mga bro...yung math naman ang ginagawa nya ay madevelope yung analytical thinking mo, maitaas yung paraaan mo ng pag iisip. habang pataas ng pataas at pahirap ng pahirap yung napag aaralan at natutuhan mong math dapat pagaling ka ng pagaling mag isip. try solving lagebra problem after you passed calculus sisiw di ba???

[bubuy]

 

7 8 1 2 5 4 9 6 3

A B C D E F G H I

 

AB = 78 / 2 = 39

BC = 81 / 3 = 27

CD = 12 / 4 = 3

DE = 25 / 5 = 5

EF = 54 / 6 = 9

FG = 49 / 7 = 7

GH = 96 / 8 = 12

HI = 63 / 9 = 7

 

i started with letter E since the only number that would be divisible by 5 in the given numbers is 5. from there trial and error na lang po ako 

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OT: ampf.. pre, di ko alam "clutch" time ka din sa math..

 

 

para di OT: can someone post the calculation of how to get the value of pi ( 3.14159.... ) alam ko calculus toh eh..

[hoopburners]

OT: ampf.. pre, di ko alam "clutch" time ka din sa math..

para di OT: can someone post the calculation of how to get the value of pi ( 3.14159.... ) alam ko calculus toh eh..

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bosing, nakikisagot lang ako dito, hehehe. pampalipas din ng oras

Edited June 7, 2005 by hoopburners

[cdma]

OT: ampf.. pre, di ko alam "clutch" time ka din sa math..

para di OT: can someone post the calculation of how to get the value of pi ( 3.14159.... ) alam ko calculus toh eh..

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Calculus is Greek to me. If I remember correctly though Pi can be calculated as accurately as desired using the series:

 

 

Pi/4 = 1/1 - 1/3 + 1/5 - 1/7 + 1/9 - 1/11 + 1/13......

 

 

Pi has an infinite number of decimal places and computers have calculated Pi to 100 million decimal places.