Prelims 2026 · CSAT / Quantitative Aptitude · Question 79
There are two chemicals which do not react with each other. A container contains 10 litres of the chemical A. One litre of this chemical is removed from it and one litre of the chemical B is poured. Then one litre of the mixture is removed from the container and one litre of B is poured. If this process of replacing one litre of the mixture by one litre of B is performed once more, then what is the volume of B that is present in the container approximately (in percentage)?<br/>
Answer
27
Each replacement leaves 9/10 of the previous amount of A.
After 3 replacements, A = 10×(9/10)^3 = 7.29 L.
So B = 10 - 7.29 = 2.71 L, i.e. 27.1% of the container.
Approximately 27%.