You work in a lab. You need a 15% acid solution for a procedure, but your supplier only sells a 10% solution and a 30% solution. You must mix the 10% solution with 30% solution to make your own 15% solution. You need 10 liters of the 15% acid solution. How many liters of 10% solution and 30% solution should you mix together?

10% solution volume =7.5 L

30% solution volume =  2.5 L

Explanation:

assume 10% solution volume is  x

So  30% solution volume = 10-x  

Required 15% solution= x volume of 10% solution+ (10-x) volume of 30% solution

0.15 * 10L= 0.1 x + (10- x)* 0.3

1.5= 0.1 x+ 3 -0.3 x

0.2 x= 1.5

x= 7.5

10% solution volume is  x =7.5 L

So  30% solution volume = 10-x  = 10-7.5= 2.5 L

I'm not really an expert on chemistry but here is a link that I believe might be helpful. https://socratic.org/questions/suppose-you-work-in-a-lab-and-you-need-a-15-acid-solution-to-conduct-a-certain-t

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).