Finding quantity of mixture In a mixture of milk and water, there is only $26$% water. After replacing the mixture with $7$ litres of pure milk, the percentage of milk in the mixture become $76$%. The quantity of mixt...--prophetes.ai

Finding quantity of mixture In a mixture of milk and water, there is only $26$% water. After replacing the mixture with $7$ litres of pure milk, the percentage of milk in the mixture become $76$%. The quantity of mixture is (a) 65 litre (b) 91 litre (c) 38 litre (d) 87 litre (e) none of these ATTEMPT Let mixture be of $x$ litres.Then water in mixture is $26x/100$ . After adding $7$ litres of milk in it ,it becomes $x+7$ litres and has $24$% water. So i get $24(x+7)/100 = 26x/100$ .Solving gives $x = 84$ .I am not sure though. Thanks for help

If we replace $7$ litres of the original mixture with $7$ litres of pure milk, we have that the final quantity of milk is: $$ \dfrac{74}{100}(x-7)+7=\dfrac{76}{100}x $$ Solving this equation we find $x$ that is the total (unchanged) quantity of mixture.