A started a business with 40000 and B joined afterward with 32000. If the profit at the end of a year was divided in the ratio 3:1 respectively, then after how much time B would have joined A?

7 months

                 A                                     B 

inv.→       40000                             32000

               × 12                                × X

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

      given→ (3                :                    1)

\(\frac{40000 × 12 }{32000× X }\)   =  \(\frac{3}{1}\)

\(\frac{15}{X}\) = \(\frac{3}{1}\)

x = 5

So, B joined after ( 12 - 5 ) = 7 Months