A mixture of 200 liters of wine and water contains 25% water. How much more water should be added so that water becomes 40% of the new mixture?

Question: A mixture of 200 liters of wine and water contains 25% water. How much more water should be added so that water becomes 40% of the new mixture?

Solution:
Number of liters of water in 200 liters of the mixture = 25% of 200 = 1/4 of 200 = 50 liters
Let us Assume that another 'P' liters of water are added to the mixture to make water 40% of the new mixture.
So, the total amount of water becomes (50 + P) and the total volume of the mixture becomes (200 + P)
Thus, (50 + P) = 40% of (200 + P)
⇒ 50 + P = (40/100) × (200 + P)
⇒ 5000 + 100P = 8000 + 40P
⇒ 60P = 3000
∴ P = 50 liters