# Noob ratio maths help

Discussion in 'General Discussion' started by Lokai, Oct 29, 2013.

1. Lokai

# Location: Wakefield

Looking for a little assistance with a maths questions for someone that hasn't studied in 18 years -

Taking two figures (380 ppm carbon dioxide and 1750 ppb methane), express the ratio of co2 to ch4 in the format x: 1, where x is a whole number given to two significant figures.

If someone could point me in the right direction it would be greatly appreciated.

2. ~>Dg<~

3. dl8860

# Location: W9

If you divide the larger number by the smaller number when both are in equal units, the number you get is the 'x' you are looking for.

5. rubberduck

# Posts: 2,646

1750 ppb = 1.75 ppm

So 380/1.75 = 217.14

So i guess the answer is 217.14 : 1

6. Lokai

# Location: Wakefield

Great, thanks for your help, i wasn't converting the methane to ppm from ppb which is where i was going wrong.

7. Freakbro

# Location: Lincs

Except it asks for a whole number to 2 significant figures, not 2 decimal places - which wouldn't be a whole number anyway.

So the answer would be 220 : 1

But well spotted on the ppb I hadn't noticed that

8. Rudeboy1

567

9. Spunkey

# Location: The land of milk & beans

Doesn't 'significant figures' mean 'integer', not nearest factor of 10? I made the answer 217:1

10. Freakbro

# Location: Lincs

No, significant figures means just that, the first set of numbers starting with one that is not zero, then you round up as normal.

So 655,464 to 3 significant figures would be 655,000
to 2 significant figures would be 660,000
and to 1 significant figure would be 700,000

Last edited: Oct 29, 2013
11. Spunkey