# Misc 13

Last updated at May 29, 2018 by Teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Misc 13 How many litres of water will have to be added to 1125 litres of the 45% solution of acid so that the resulting mixture will contain more than 25% but less than 30% acid content? Volume of existing solution = 1125 litres Amount of acid in it = 45% of 1125 Hence, amount of water in it = 55% of 1125 = 55 100 1125 Let amount of water added be x litres So, Volume of new solution = 1125 + x Now, given that the new solution will contain more than 25% acid content Hence, 25 % of (1125 + x) = 506.25 25 % (1125 + x) = 506.25 25 100 (1125 + x) = 506.25 1 4 (1125 + x) = 506.25 1 4 (1125 + x) = 506.25 (1125 + x) = 506.25 4 1125 + x = 2025 x = 2025 1125 x = 900 Similarly, maximum acid content is 30% Hence, 30 % of (1125 + x) = 506.25 30 % (1125 + x) = 506.25 30 100 (1125 + x) = 506.25 3 10 (1125 + x) = 506.25 (1125 + x) = 506.25 10 3 (1125 + x) = 1687.5 x = 1687.5 1125 x = 562.5 Hence, acid content should be between 25% and 30% i.e. amount of water added should be between 900 & 562.5 litres i.e. 562.5 < x < 900

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.