Multiple choice

A solution of salt and water contains 30% of salt by weight. If 40 liters of water evaporates and the solution contains 45% of salt, then find the original quantity of solution.

  1. 150 litre

  2. 130 litre

  3. 120 litre

  4. 140 litre

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let original solution = x liters. Salt = 30% of x = 0.3x. After evaporation: 40 liters water removed, so new volume = (x - 40) liters. Salt is now 45%: 0.3x/(x-40) = 45/100 = 0.45. Solving: 0.3x = 0.45(x-40) → 0.3x = 0.45x - 18 → 0.15x = 18 → x = 120 liters. Option C matches.

Keep practicing — related questions