A can contain a mixture of two liquids P amp Q in proportion 3 5 When 8ltr of mixture are drawn off ...........

Explanation:

                             P…………..Q
initial                      3…………….5
after                        3……………..7
7-5 = 2
2 =8
1 =4
after (7+3) =10= 40ltr
so initial = 3/3+5*40 = 15ltr

Hence, option 1 is the correct answer.