More Math Help Needed Please.

[ferlew]

I'm struggling to work out the GSM of some card I have promised someone.I weighed 10 sheets to get a more accurate reading, and that was 160gr.
One sheet is 210mm by 300mm, which I think converts to 0.06 of a square metre, and weighs 16 gr.
How on earth can I work out the grams per square metre please.
Totally lost it here this afternoon trying to get the correct answer.
Grateful for any help, thanks.

[fiction-factory]

One sheet = 0.21 x 0.3= 0.063 sq m
g/sq m = 16/0.063

[fiction-factory]

=253.97 g/sq m.
Call it 254?

[Buenchico]

I agree with FF.

Rounding the answer to that calculation yields 250 gsm which is, reassuringly, a commonly sold card thickness . e.g. here:
https://www.amazon.co.uk/100-Sheets-250gsm-White-Card/dp/B00TQUPV72

[fiction-factory]

Yes- 250 seems a good answer- 2 significant figures seems appropriate here

[margarettom]

Probably not the best method but I did
0.063 = 16
x both sides by 100
6.3 = 1600
1 = 1600/6.3 = 254 ( approx)

[New Judge]

Just the one math, is it!?

[Mamyalynne]

Stick around there'll be another any minute NJ, grab it quick.

[sanmac]

I think that NJ is referring to the American way of using "math" instead of "maths". However, I could be wrong.

[jim360]

It's one of NJ's favourite ongoing campaign.

[Mamyalynne]

Well, I didn't think he'd come to assist.

[THECORBYLOON]

JIM are you sure it's not one of his favorites?

[ferlew]

Many thanks indeed, just could not fathom the equation.
Son thought he was being helpful telling me it was 11/1000ths of an inch thick - did not help at all, thanks again, I'll settle for 250, was hoping it would be more of a 300 gsm. Ta all.

[ferlew]

New Judge, not just the one math, fingers didn't keep up with my brain.

[THECORBYLOON]

The card should be A4 size or 297mm x 210mm. A0 size is 1m² and the A4 size is 1/16th of the A0.

That means you need to weigh sixteen sheets as they will cover 1m² and that will give you the gsm.

[sanmac]

And while we're at it, happy Labor Day, Monday, across the pond:)

[New Judge]

"New Judge, not just the one math, fingers didn't keep up with my brain."

In that case you're forgiven! :-)

[Peter Pedant]

whats wrong with 'maff' ?

[fiction-factory]

I'd never realised paper size A0 was defined as 1m², thecorbyloon, but it makes perfect sense. So A1 is ½m² , A2= ¼m² , A3 = ⅛m² and A4 is (1/16)m² . Thanks.
So if ferlew's weight figure for 10 sheets was accurate the weight of 16 would be 256g, so the GSM would be 256g/m²

[fiction-factory]

I think Buenchico's figure of 250 will be right. Based on that figure and 1/16th of a square metre the weight of each card would be 15.625g, so the weight of the 10 ferlew weighed should have been 156.25g which could have been read as 160g with a bit of rounding, slight inaccuracy of the scale, maybe dust on the card and and possibly some parallax error

[ferlew]

And all the above answers are exactly what I do like about Answerbank.

Brilliant tip from Thecorbyloon re one A4 sheet being 1/16, will remember that in future, and weigh card in 16's :)
Thanks all.