A invested Rs.3000 and after some time B joined him by investing Rs.4000. After one year they acquire the same profit, after how many months did B join A?
Let the time of investment of `x'
Investment of A ×time of investment of AInvestment of B ×time of investment of B = Profit of APtofit of B
3000 ×12 4000 × x=1
x = 9
So B joined after 3 months.