Question

How much water mus be evaporated from 400 gallons of a 15% saline solution to get a 40% saline solution?

Answer 1

amount of saline is .15 X 400 gal = 60 gal.
now you want to reduce the water by evaporation so that 60 gal is 40 % of the total.
Is this enough to get you headed in the right direction?

Answer 2

Let us call the required amount of water x so that .40x=60 solve for x
x=60/.40 = 150 gal of water. Next figure out how much water you have! You have 400 gallons of a mixture of which 60 gal is saline. Water would then be 400-60=340 gallons.
Now we are about finished. You need 150 gal, you have 340 gal, how much do you need to let evaporate?

Answer 3

i am so confused

Answer 4

What is the point of confusion?

Answer 5

i just dont understand math at all

Answer 6

Do you know how to convert per cent (%) to a decimal value?

Answer 7

no

Answer 8

wait yes

Answer 9

To convert to decimal move the decimal two places to the left (you are dividing by 100)
per cent means per hundred. If you have 400 gallon water/saline mixture that is 15% saline then to determine the amount of saline you would convert 15% to a decimal .15 and multiply it by the 400. If it was 50% solution you would multiply by .5 which will result in the amount of saline (half of it)

Answer 10

How many gal of saline is in the 400 gallons of 15% saline water mixture?

Answer 11

Step 1 : convert 15% to a decimal
Step 2 : multiply 400 gal by the result of Step 1.
Step 3 : you have the amount of saline that is present in the 400 gal solution.
How much saline is in the 400 gal solution?

Answer 12

Good luck with it. Hopefully the confusion will evaporate also.