[Discussion] Anyone Good in mathemathics?

[Luther]

I dont understand how his answer changed from 350ml to 400 can anyone help me with the steps or tell me how to go about it?@ 3:30
Is there anyone good in mathematics over here? If so how do i get the least number of significant digit of 0.15 i know its 0.2 but how are the steps?

 

[Sasori]

Off topic, but Your sig .

 

[Υαmí]

If it's 5 and up, the 1 would turn into a 2..... I suck at math, most of the time.....

Example: .34 ( you can't round that up, as the 4 is to small a number, so the number stays the same)

Edit: did not see that new part, never mind.

 

[Pumpkin Ninja]

I think he just rounded it to 400 because he needed 1 significant digit only. Since it was 350 it was rounded up to 400, if it was 349 he would of rounded it to 300 ml.

 

[CloyEscapade]

I think he just rounded it to 400 because he needed 1 significant digit only. Since it was 350 it was rounded up to 400, if it was 349 he would of rounded it to 300 ml.

Winter must be coming, cuz I read your name as pumpkin latte ninja

 

[Pumpkin Ninja]

Winter must be coming, cuz I read your name as pumpkin latte ninja

But it's still my month...

 

[dms_kakashi]

Significant digit is counted from right. O is neglected at beginning.

2nd SD@@@ 2566:From right count to two. It goes to 5 so ans. 2500 and since 6 is >=5, 2600

3rd SD:0.6564:0.656 :0 is neglected while counting

What is ur grade?
For 1 SD

0.15: count to 1st digit neglecting zero at first step.
It results to 0.1
So:0.1
Again after 1 there is 5 which is >=5, so 0.2

If u have any prob in maths consult me. I would try my best.

 

[Hexuze]

That's more science help than math. :l

 

[Transcendence]

Yes, I got 90 or over in all my Math courses in High School and I'm taking Calculus in University as well.

As for your question, this isn't just Math, it's Chemistry related. The standard rules of Math don't apply. My plug-in isn't working at this present moment, but judging from your question, it has to do with significant digits, which was the reason number changed, as it was rounded up. This is all dependent on the numbers you use in your calculations, as the number with the least significant digits will dictate the number of significant digits you round to in your final answer (which is the same as the one with the smallest amount of significant digits).

 

[Zee Seh]

Well. You have to round off 350 to the nearest hundreds.. Ryt? In such cases. You look at the digit at tens place. If its 0-4 then round down. if 5-9 round up.
In this particular case. its 5 at the tens place. so u'll round up to 400. If it was 340 or sumthin. It would be 300.

 

[Uzumaki Naruta]

I dont understand how his answer changed from 350ml to 400 can anyone help me with the steps or tell me how to go about it?@ 3:30
Is there anyone good in mathematics over here? If so how do i get the least number of significant digit of 0.15 i know its 0.2 but how are the steps?

With calculations 350 ml is correct.

I tried understanding why of he changed to 400ml but he only said 2 words about it that doesn´t explain anything in my opinion.

My assumption is that, when the isopropyl alcohol is mixed with water, a small amount of alcohol will break up leaving ions in the water. Those ions don´t count in the 70% v/v. So when you used 350 ml of solute, a portion of it will dissolve causing the percentage to decrease. And to get the wanted percentage, you´ll have to put more so after some of them is dissolved, the concentration left is 70% v/v.



And about your second question: I´m not sure if I understood what you mean.
If you ask why 0,15 end up being 0,2 at one significant digit, then it´s because you approximate the "additional" digit (You round up when the digit is 5 or above; and you don´t change anything when the digit is 4 or below)

 

[Strawberry]

the asnwer is 7