Discussion
How many ounces of water must be added to a 30-ounce solution that is 40 percent alcohol to dilute the solution to 25 percent alcohol?
*This question is included in Nova Math - Diagnostic/Review:, question #26
| (A) | 9 |
| (B) | ... |
| (C) | ... |
| (D) | ... |
| (E) | ... |
| (F) | ... |
The solution is
Posted: 02/06/2013 11:44
The solution seems to be a bit over complicated. It's a simple concentration formula of C1V1 = C2V2. Where you solve for V2, which is the final volume needed for C2, which is the final concentration desired.
40%(30) = 25%(V2)
V2 = 48
Subtract the original volume from the final volume needed to get the answer of 18 to be added.
40%(30) = 25%(V2)
V2 = 48
Subtract the original volume from the final volume needed to get the answer of 18 to be added.
Posted: 10/11/2013 08:38
I prefer this simpler method. How did you come up with V2=48? I think I'm missing something.
Posted: 12/22/2013 18:59
Why did you multiply 30 oz. by 40 instead of .4? Same with 25?
Posted: 12/22/2013 19:05
In the equation C1V1 = C2V2, it doesn't matter. As long as both sides of the equation are using the same units. You get the same answer, but if you use 40 (because you are leaving it as a percent), then you need to use 25 on the other side; if you use .4 then you have to use .25.
Posted: 12/22/2013 19:05
*Duplicate comment
Posted: 09/23/2014 07:32
I'm confused
40 multiplied by 30 = 1200
1200 divided by 25 = 48
V2 = 48