Looks like a strange question but is actually doable.
From Q stem, I ascertained the follows:
2x:x is the ratio of the concentration of acid in sol 1 to that in sol 2
Then I set 2x=.5 and x=.25
This gave me .8/1.6=.5 and .6/2.4=.25
I noticed something interesting here, 1.6+2.4=4 and 4*2.5=10.
So when I multiplied 1.6 by 2.5 and voila, I got 4.
@Bunnel
chetan2u, is this approach correct? Also, how can I tell if a question is worth spending more than 2 mins.
Many many thanks in advance!!!