ATAR Notes: Forum

VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE General & Further Mathematics => Topic started by: TyErd on October 31, 2010, 10:20:56 pm

Title: help
Post by: TyErd on October 31, 2010, 10:20:56 pm: How do you do this question? Its from number patterns.
Title: Re: help
Post by: BSKT on October 31, 2010, 10:29:27 pm: I got 500. Is that the answer?
Title: Re: help
Post by: TyErd on October 31, 2010, 10:43:44 pm: nah its 300mL
Title: Re: help
Post by: jasoN- on October 31, 2010, 10:47:18 pm: Okay you have 20% of 200 mL is detergeant. (ie. 40mL detergeant)
If you want to make it 8%
$\frac{40}{x} = 8%$ %
Know that 8% is 0.08
$\therefore x = \frac{40}{0.08} = 500mL$

As you initially have 200 mL, you hence have to add 300 mL
Title: Re: help
Post by: BSKT on October 31, 2010, 10:54:22 pm: oh yeah sorry i forgot to minus the initial 200 >_<
Title: Re: help
Post by: jasoN- on October 31, 2010, 10:55:35 pm: Just cause i can, C1V1 = C2V2 also works =)
Title: Re: help
Post by: dec0da on October 31, 2010, 10:59:19 pm: :OMG I HATE THIS QUESTION !!!! oh i got it wrong and didn't know why, thanks ppls :smitten:
Title: Re: help
Post by: TyErd on October 31, 2010, 11:01:41 pm: Quote from: jasoN- on October 31, 2010, 10:55:35 pm
Just cause i can, C1V1 = C2V2 also works =)

whats that?
Title: Re: help
Post by: jasoN- on October 31, 2010, 11:02:23 pm: sorry that is chemistry, i was just joking around
and to those who didn't get my method above
40/200 = 20%
therefore 40/x = 8%, where x is the total volume of water (0% conc) required
Title: Re: help
Post by: TyErd on October 31, 2010, 11:13:38 pm: Quote from: jasoN- on October 31, 2010, 11:02:23 pm
sorry that is chemistry, i was just joking around
and to those who didn't get my method above
40/200 = 20%
therefore 40/x = 8%, where x is the total volume of water (0% conc) required

oh lol ok. that method you just did makes it easier to understand. Thanks!