Hi, I have a question about this problem; how do you solve it? And what are the rules for sig fig? It says the answer is C. How?

Here, you can use this handout to answer that: https://www.chemtopperquiz.com/pluginfile.php/10214/mod_resource/content/1/Scientific%20notations%20and%20Significant%20figures%20.pdf

So, to answer your question, you first do 69+6, not 69+6.167, because if you look in the rules, it says you have to take the number of decimal places as the limiting number or the number with the least number of decimal places for your answer, in this case, 69, because it has 0 decimal places. So, 69+6=75. And then you divide 75 by 5, not 5.10, because you take the number of decimals places as the limiting number, in this case 75, so 75/5 = 15.
So, 15/C is correct.

QuoteSo, 69+6=75. And then you divide 75 by 5, not 5.10, because you take the number of decimals places as the limiting number, in this case 75, so 75/5 = 15.

Avni this part is wrong .For the numerator add 69 and 6.167 which is equal to 75.167 and now drop all numbers after decimal and round off. So it becomes 75 and now divide by 5.10 and round off to two sig-fig.
Now answer is 14.7 which can be rounded off to 15.
Every time you need to round off to correct sig -fig.

Ooh, so you round off after not before. Ok thanks