Hi,
I think you might be lost on wordings.
So total volume of mixture \(= 120\)ml
Qty of \(X = 40\)% of \(120 = 48\)ml
A part of the mixture was removed and replaced with an equal quantity of water.
Let's say \(p\) ml is removed and replaced with water. Now \(p\) will contain \(40\)% of \(X\) as well.
So, after removing \(p\) ml
qty of \(X = 48 - 0.4 p\)
If the resulting mixture contained \(10\)% of \(X\)
Now the resulting mixture is \(120\)ml so qty of \(X = 12\)ml
\(X = 48 - 0.4 p = 12\)
\(p = 90\) ml
Please ask if the doubt remains.
aishumurali wrote:
sorry this sum is easy for some but i dont understand.
The mixture first contains 40% chemical x , 40% of 120 is 48 litres
Then the mixture contains 10% chemical x , which is equal to 12 litres
48 - 12 = 36 litres
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