Question

After 30 kg of water were evaporated from a solution of a salt and water which had 15 percent of salt, the remaining solution has 20 percent salt. The weight of the original solution is

Answer 1

Let Mixture was X initially.

Initial Salt = 15% of X = 0.15X.

Initial Water = 85% of X = 0.85X.

30 liter of water evaporated.

So, Final water = (0.85X - 30).

Now, salt rises to 20% of the mixture, it means as water dried up salt rises.

Now, Total Mixture = (0.85X -30 + 0.15X).

Final salt = 20% of(0.85X - 30 + 0.15X)

As, Initial Amount of salt = Final amount of salt, we have,

0.15X = 20% of(0.85X - 30 + 0.15X)

0.15X = 0.20X - 6.

Or, 0.5X = 6.

Thus, X = 120.

Initial amount of the mixture was 120 litre.