rakeshd347 wrote:Two solutions of acid were mixed to obtain 10 litres of new solution.Before they were mixed,the first solution contained 0.8 litres of acid while the second contained 0.6 liters of acid. If the Percentage of acid in the first solution was twice that in the second,what was the volume of the first solution?
a.3 litres
b. 3.2 litres
c.3.6 litres
d.4 litres
e. 4.2 litres
An alternate approach is to PLUG IN THE ANSWERS, which represent the volume of the first solution.
When the correct answer choice is plugged in, the percent of alcohol in the first solution will be twice the percent of alcohol in the second solution.
It is almost certain that the amount of acid in the first solution -- 0.8 liters -- will divide easily into the correct answer choice, so that the percent of alcohol in the first solution is equal to an integer value.
Thus, the correct answer choice is probably B (since .8/3.2 = 8/32 = 1/4 = 25%) or D (since .8/4 = 8/40 = 1/5 = 20%).
Since answer choice D is an integer value, start with D.
Answer choice D: first solution = 4 liters, second solution = 6 liters
In the first solution, alcohol/total = .8/4 = 8/40 = 1/5 = 20%.
In the second solution, alcohol/total = .6/6 = 6/60 = 1/10 = 10%.
Success!
The correct answer is
D.
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