A salt solution has 5% salt. If 100 litres of water evaporated, the amount of salt is 15%. How much was the solution in the Beginning?

150

5% = \(\frac{1}{20}\)

15% = \(\frac{3}{20}\)

                                    Salt         Water

Before evaporation            1              19

After evaporation             3               17

*The quantity of the salt must be same before and after evaporation*

                                    Salt         Water

Before evaporation     3×( 1              19 )

After evaporation             3               17

                                    Salt         Water

Before evaporation           3               57

After evaporation             3               17

Water evaporated = 57 - 17 = 40             (57 + 3)= 60 (Total)

                                         ↓                              ↓

                                      ×2.5                          ×2.5

                                         ↓                              ↓

                                 100 (Given)                      150