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confusing maths question?!

I really need help with this question!!
you need to make a 100ml solution of potassium permanganate of which when one part is diluted with seven parts of water makes a 1 in 4000 solution. How much potassium permanganate is required?

Reply 1

Smaug123

Original post by Bubbles!

The question makes no sense, as far as I can tell. One part diluted with seven parts should make a 1 in 7 solution.

Reply 2

shorty.loves.angels

1:7 parts is the same as '1 in 8' as far as I know.

If it needs to be 1 in 4000 then the potassium permanganate should be 1/500 (as 8 x 500 = 4000) so 0.002 %

100 / 8 = 12.5 so 12.5ml of 0.02% (might not be %... concentration??) potassium permanganate + 87.5ml (as 12.5 x 7 = 87.5) water would give the 1:7 ratio.

Does this work for the context?

Reply 3

Smaug123

Original post by Smaug123

The question makes no sense, as far as I can tell. One part diluted with seven parts should make a 1 in 7 solution.

Original post by shorty.loves.angels

1:7 parts is the same as '1 in 8' as far as I know.

In my defence, I was very tired when I replied :P

Reply 4

shorty.loves.angels

Original post by Smaug123

In my defence, I was very tired when I replied :P

Got so confused when I saw this. I drank wine last night and really don't remember being on TSR.

Don't worry, I used to be a science technician, if that consoles you? :tongue:

Reply 5

Smaug123

Original post by shorty.loves.angels

Got so confused when I saw this. I drank wine last night and really don't remember being on TSR.

Don't worry, I used to be a science technician, if that consoles you? :tongue:

Very much - I'm a lowly maths student, I don't know these engineeringy dark arts…