In what ratio P:Q should the Mixture P of milk and water in the ratio of 5:4 be mixed with another Mixture Q of milk and water in the ratio 2:7 so that the resultant mixture contains equal quantities of milk and water? Choose the correct choice:
A) 3 : 2  B) 2 : 1  C) 4 : 3  D) 4 : 1  E) 5 : 1

Rationale: ( 5 / 9 ) * p + ( 2 / 9 ) * q = ( 4 / 9 ) * p + ( 7 / 9 ) * q p = 5 q p / q = 5 / 1 the answer is e .
Answer: E