A and B started a partnership business investing some amount in the ratio of 3 : 5. C joined them after six months with an amount equal to that of B. In what proportion should the profit at the end of one year be distributed among A, B and C ?

A. 3 : 5 : 2
B. 3 : 5 : 5
C. 6 : 10 : 5
D. Data inadequate
E. None of these

Explanation :

Let the initial investments of A and B be 3x and 5x.
A : B : C  = (3x x 12) : (5x x 12) : (5x x 6)
               = 36 : 60 : 30
               = 6 : 10 : 5.