rvthryet wrote:

Bunuel wrote:

Well don't know how you did it, but here is my way:

Salinity=3.7%

Water=64

Salt in it=64*3.7%=2.368

We need 2.368 to be 4.5% --> x*4.5%=2.368 --> x=52.62. So we should evaporate 64-52.62=11.37

This is the exact way that i followed.. But is there a standard formula that i can use for such questions?

You can use formula but the formula changes as the question changes. You can have formula for every problem in gmat but thats not possible to remember. So its better to understand the problem and use the logic to solve it.

Trying to remember and use formula in gmat probably costs you too much because there are hundreds of formulas to be remembered. Try to remember as few formulas (that are must) as possible.

_________________

Verbal: http://gmatclub.com/forum/new-to-the-verbal-forum-please-read-this-first-77546.html

Math: http://gmatclub.com/forum/new-to-the-math-forum-please-read-this-first-77764.html

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT