I can't figure out how to make an equation for the problem. The problem is: To reduce 16 ounces of a 25% solution of antiseptic to a 10% solution, how much distilled water should a nurse add? The nurse should add ???? oz. of distilled water.
2006-11-30 16:58:28 · 7 answers · asked by AG 2 in Science & Mathematics ➔ Mathematics
24 ounces
2006-11-30 17:54:03 · answer #1 · answered by Kristina G 1 · 0⤊ 0⤋
24 ounces of distilled water.
Here's how I solved it:
The 16 oz. 25% solution contains 4 oz. of the pure antiseptic. A 10% solution made from that 4 oz. would be 40 oz. The difference between the 16 oz. of the 25% solution and the 40 oz of the 10% solution is 24 oz.
There's probably a better, more formal way of setting up the problem, but it's the solution I came up with.
2006-12-01 01:12:31 · answer #2 · answered by DavidNH 6 · 0⤊ 0⤋
Solve like this:
25% of the solution is antiseptic, therefore 75% is water. In 16 oz. of water that equates to 16 x 25% = 4 oz. of solution is antiseptic.
The resulting solution (as we only add water) must contain 4 oz. of antiseptic, and represent 10% of the new total mix. The total mix will be 40 oz.
We have 16 oz. already so have to top up to 40 oz i.e. 40-16=24 oz. of water will be added. We'll now have 40 oz. of solution of which 10% (4 oz.) is antiseptic.
The mathematic formula to solve:
water to add = ( ( initial solution volume * initial percentage antiseptic ) / desired percentage antiseptic ) - original solution volume
i.e.
24 = =( (16*25%)/10% ) - 16
2006-12-01 01:19:48 · answer #3 · answered by Andre S 1 · 0⤊ 0⤋
16 oz of 25%=16/4=4 oz of antiseptic. to get 10% 4/.10=40 oz
40-16=24 of of water must be added.
2006-12-01 01:13:24 · answer #4 · answered by yupchagee 7 · 0⤊ 0⤋
Let's see. If you have 16 oz. of a 25% solution of antiseptic, then you have 4 oz. (=16 x 25%) of antiseptic.
To make a 10% solution with those 4 oz., you'll need a total of 40 oz. of solution (4 oz. / 40 oz. = 10%).
To increase your 16 oz. to 40 oz., add 24 oz. of water (16 oz. + 24 oz. = 40 oz.).
Answer = 24 oz.
2006-12-01 01:05:26 · answer #5 · answered by actuator 5 · 1⤊ 0⤋
This is not so hard as you think to set up as you just have some equality equations.
One one side you have 16oz times 25%
One the otherside you have some unknown amount Xoz times 10%
So 16 x 25 = X x 10
or 16 x 25 / 10 = X
Remember X will be your total final volume of solution so you in the end just have to subtract your starting volume:
Xoz - 16oz = the amount of water that you add.
Cheers and keep trying!
2006-12-01 01:09:18 · answer #6 · answered by timor_abesto 1 · 0⤊ 0⤋
24 oz
2006-12-01 01:13:53 · answer #7 · answered by garyedwardjohnston 3 · 0⤊ 0⤋