Math gurus help me out

[DLI848]

Here's my problem:

4.25 lb into grams (1kg=2.20 lb)

I need the steps on how to solve this problem, as in what to convert first and stuff because I have to show my work. I used a conversion calculator and got 1927 grams, but I keep coming up with 1931 grams.

[Meyatch]

4.25 Lb x 1kg/2.20lb x 1000g/kg

[Meyatch]

and I get 1931.81 g

You get a different answer because 1 kg = 2.20462262 pounds.

[basstotheface]

conversion rate is 454 g per lb, at least that's how I remember it, so you can use cross products and do the rest.

[DLI848]

Originally Posted by Meyatch

and I get 1931.81 g

You get a different answer because 1 kg = 2.20462262 pounds.

How would I write that in correct significant figures?

[bassman03]

What's the number with the least amount of significant figures in your steps to get there?

[m0nst3r]

4.25 lbs/2.2 lbs = 1.9318 kg

1.9318 kg x 1000 g = 1931.81 g

Your answer is right, but the reason you're getting a different answer is because of a rounding error. As Meyatch already pointed out, if you use the figure he gives you, you'll get 1927.

[DLI848]

Originally Posted by bassman03

What's the number with the least amount of significant figures in your steps to get there?

3 sigs, but if i made the answer with 3 sigs, it wouldn't be correct.

[DLI848]

Originally Posted by m0nst3r

4.25 lbs/2.2 lbs = 1.9318 kg

1.9318 kg x 1000 g = 1931.81 g

Your answer is right, but the reason you're getting a different answer is because of a rounding error. As Meyatch already pointed out, if you use the figure he gives you, you'll get 1927.

What would be the correct amount of significant figures?

[DLI848]

Nevermind about the sigs. I'm braindead from doing chemistry homework. 1930 would be the correct answer to get the number of sigs. Thanks for the help guys!

[fdeck]

Google "4.25 lb to grams"

I know this isn't how you need to solve your math problem, but it's cool that Google provides this feature.

[jp58]

When multiplying numbers, use the same number of significant figures as the smallest number (of sigfigs) from the beginning of the problem.

4.25 lb. has 3 significant figures, so your answer should (in theory; YMMV with your professor) contain 3 sigfigs.

[ehque]

Originally Posted by jp58

When multiplying numbers, use the same number of significant figures as the smallest number (of sigfigs) from the beginning of the problem.

4.25 lb. has 3 significant figures, so your answer should (in theory; YMMV with your professor) contain 3 sigfigs.

Correct, although considering the sig fig of all data you are using in your calculation is important. In this case, the conversion factor also has 3 sig fig and hence you answer should have 3 (the lowest of the data)

[Johnny BoomBoom]

If you take the 4.25 lbs and multiply ib by the 454 grammes per pound, you get 1929.5g......a nice number, but that's not using the data you've been given!