for word problem expert

Question

how many kg of pure salt must be added to 30 kg of 2% solution of salt and water to increase it to a 10% solution

 

means in 30kg 2% is solution of water and salt then what is 28 kg and if add pure salt upto 10 % then 30kg solution increased  

 

 

i am not understood question please explain me in detail

Answer 1

If your solution of salt water with 2% salt weighs 30kg, then 2% of that 30kg is salt. To find 2% of 30kg, calculate:

 

30kg solution  *  0.02 (0.02 is equivalent to 2%)  =  0.6kg salt

 

To find the mass of just the water, subtract the mass of the salt in the 2% solution.

 

30kg water+salt  -  0.6kg salt  =  29.4kg water

 

That's the mass of the water in the solution before it was a solution and before there was salt in the water. Once the 0.6kg of salt was added to the water, it became a 2% solution of salt water with a mass of 30kg. Now, to find the amount of salt that we would have to add to make this base number (just water) a 10% solution, we do the same as above and calculate (only using our new mass):

 

29.4kg solution  *  0.10 (0.10 is equivalent to 10%)  =  2.94kg salt

 

Then, you add that to the water mass

 

29.4kg water  +  2.94kg salt  =  32.34kg saltwater solution

 

That's the total mass of the saltwater solution after you've added the new amount of salt so if you take the difference between this number, and the original mass of 30kg, it will give you the amount that you have to add to the original to get a 10% solution. So, let's calculate:

 

32.34kg saltwater solution (10% solution)  -  30.00kg saltwater solution (2% solution)  =  2.34kg SALT ADDED

 

 

 

If I'm full of it, somebody please let me know because I wouldn't trust me on this. I just hope this can get the wheels rolling in your head.