A mixture is said to be symmetrical if it contains liquids P and Q in ratio 1 ∶ 2. 40 liters of a mixture of P and Q is taken in which P and Q are in the ratio 2 ∶ 3. What should be the ratio of P and Q in 20 liters of mixture that when mixed with first mixture results in a symmetrical mixture?
1
1 ∶ 2
2
1 ∶ 3
3
1 ∶ 4
4
1 ∶ 5
5
2 ∶ 7