A started a business with 45000 and B joined afterward with 30000. If the profit at the end of a year was divided in the ratio 2:1 respectively, then B would have joined A for business after.

3

                 A                                     B 

inv.→       45000                             30000

               × 12                                × x

profit→   -----------------------------------------

      given→ (2                                    1)

\(\frac{45000 × 12 }{30000×x }\)   =  \(\frac{2}{1}\)

\(\frac{18}{X}\) = \(\frac{2}{1}\)

x = 9

So, B joined after ( 12-9 ) = 3 Months