# Equation

• Nov 22nd 2007, 08:57 AM
bassmansam
Equation
Hi guys just wondering if you could help me out with this question i know the answer is 10 but im not sure how the eqution is set up?
The amount of sleep ( s hours) a child needs depends on its age (A years)., and is given bu the foruma above S=15-1/2 (half)A

If a girls age is equal to the number of hours she should be sleeping how old is she
Thanks

Sam
• Nov 22nd 2007, 09:01 AM
bassmansam
Mistake
OOps this is in the wrong forum sorry
• Nov 22nd 2007, 09:02 AM
janvdl
Quote:

Originally Posted by bassmansam
Hi guys just wondering if you could help me out with this question i know the answer is 10 but im not sure how the eqution is set up?
The amount of sleep ( s hours) a child needs depends on its age (A years)., and is given bu the foruma above S=15-1/2 (half)A

If a girls age is equal to the number of hours she should be sleeping how old is she
Thanks

Sam

$S = 15 - \frac{1}{2} A$

$S = A$ (Given)

So S and A = $x$

$x = 15 - \frac{1}{2} x$

[Multiply both sides by 2]

$2x = 30 - x$

$3x = 30$

$x = 10$
• Nov 22nd 2007, 09:03 AM
janvdl
Quote:

Originally Posted by bassmansam
OOps this is in the wrong forum sorry

Isn't this a middle school problem?
• Nov 22nd 2007, 09:35 AM
bassmansam
im at university so i would guess it is a university question?
• Nov 22nd 2007, 09:41 AM
janvdl
Quote:

Originally Posted by bassmansam
im at university so i would guess it is a university question?

I'm not trying to be funny, but I did stuff like this in grade 10...
• Nov 22nd 2007, 09:42 AM
bassmansam
well i am from england, maybe that is why?
• Nov 22nd 2007, 09:44 AM
janvdl
Quote:

Originally Posted by bassmansam
well i am from england, maybe that is why?

What are you studying, if i may ask?
• Nov 22nd 2007, 09:46 AM
bassmansam
Im studying Computing
• Nov 22nd 2007, 09:48 AM
janvdl
Quote:

Originally Posted by bassmansam
Im studying Computing

Oh that explains it. It's not very heavy on maths.