Ravi and Kavi start a business by investing Rs. 8000 and Rs. 72000, respectively. Find the ratio of their profits at the end of year.
A and B start a business such that their initial investment is Rs. 3000 and Rs.4000 respectively. C joins them after 7 months by investing some amount. After one year the ratio of profit share of B to that of C is 8:5. Find the ratio of the investment of A to that of C.