Question

Please Help Me.......

(Q) A 12L cylinder contains a mixture of oxygen and nitrogen, the volume of oxygen being 40% of total volume. A few litres of the mixture is released and an equal amount of nitrogen is added. Then the same amount of the mixture as before is released and replaced by nitrogen for the second time. As a result, the oxygen content becomes 10% of the total volume. How many liters of mixture is released each time?

Answer 1

at first the amount of oxygen is 40% of 12l =4.8l
At the end the amount is 10% of total volume = 10% of 12l = 1.2l
So, the change in volume is (4.8-1.2)l = 3.6l
so, we can say that 3.6l of oxygen was released at 2 times, hence at once (3.6/2)l = 1.8l of oxygen was released.