# Riddle help

• Oct 24th 2007, 04:58 PM
jak
Riddle help
I need help with a riddle hoping someone can help

Mandy is 25 years older than Sandy
Sandy is 25 yrs younger than Mandy

Mandy's age is even
Sandy's age is odd

Together the sum of their ages is 63 how old is each sister?

anyone?
• Oct 24th 2007, 05:13 PM
Jhevon
Quote:

Originally Posted by jak
I need help with a riddle hoping someone can help

Mandy is 25 years older than Sandy
Sandy is 25 yrs younger than Mandy

aren't these two statements redundant?

Quote:

Mandy's age is even
Sandy's age is odd

Together the sum of their ages is 63 how old is each sister?

anyone?
this isn't a riddle.

since Sandy's age is odd, we can write it as: $2n + 1$ for $n \in \mathbb{N}$ ...(i used the natural numbers instead of the integers since negative ages make no sense, but whatever).

since Mandy is 25 yrs older than Sandy, Mandy's age is given by:
$2n + 1 + 25 = 2n + 26$

The sum of their ages is 63, thus we have:

$2n + 1 + 2n + 26 = 63$

now solve for $n$ and you will be able to find their ages
• Oct 24th 2007, 07:37 PM
Soroban
Hello, jak!

What a silly problem!
Where did it come from?

Quote:

Mandy is 25 years older than Sandy.
Sandy is 25 yrs younger than Mandy. . . . . well, duh!

Mandy's age is even. . . . . Not relevant
Sandy's age is odd. . . . . . Who cares?

Together the sum of their ages is 63. . . . . Finally, something useful!

How old is each sister?
They're sisters? .Boy, that's really important!

(That's quite an age spread for siblings, isn't it?)

Let $S$ = Sandy's age.
Then $S + 25$ = Mandy's age.

"The sum of their ages is 63": . $S + (S + 25) \:=\:63$

• Oct 24th 2007, 08:02 PM
Jhevon
Quote:

Originally Posted by Soroban
Mandy is 25 years older than Sandy.
Sandy is 25 yrs younger than Mandy. . . . . well, duh!

Mandy's age is even. . . . . Not relevant
Sandy's age is odd. . . . . . Who cares?

Together the sum of their ages is 63. . . . . Finally, something useful!

How old is each sister?
They're sisters? .Boy, that's really important!

(That's quite an age spread for siblings, isn't it?)

Indeed! I guess the way the question was phrased is supposed to be the riddle, and i fell for it, working too hard. oh well, it happens
• Oct 25th 2007, 02:14 AM
dravid2
sandy is 44 while mandy is 19
• Oct 25th 2007, 01:38 PM
jak
sorry for wasting everyones time thanks for the response. After I posted it, I realized duh as many had suggested....

anyway thanks for the help
• Nov 29th 2007, 01:11 PM
ivananeedshelponmath2
hmm
Quote:

Originally Posted by jak
I need help with a riddle hoping someone can help

Mandy is 25 years older than Sandy
Sandy is 25 yrs younger than Mandy

Mandy's age is even
Sandy's age is odd

Together the sum of their ages is 63 how old is each sister?

anyone?

i think that mandy is 50 and sandy is 25 but i might be wrong
• Nov 29th 2007, 09:14 PM
Jhevon
Quote:

Originally Posted by ivananeedshelponmath2
i think that mandy is 50 and sandy is 25 but i might be wrong

50 + 25 = 75. we are told the sum of their ages is 63