Rahul and Bharti are partners in a business. Rahul contributes $$\frac{1}{4}$$th capital for 15 months and Bharti received $$\frac{2}{3}$$ of profit. For how long Bharti money was used
a) 8 months
b) 10 months
c) 11 months
d) 17 months

Answer: b
Explanation:
$$\eqalign{ & {\text{Let}}\,{\text{the}}\,{\text{total}}\,{\text{profit}}\,{\text{be}}\,Rs.\,Z \cr & {\text{Bharti’s}}\,{\text{share}} = {\frac{2}{3}} Z \cr & {\text{Rahul’s}}\,{\text{share}} = Z – {\frac{2}{3}} Z \cr & \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \frac{Z}{3} \cr & {\text{Rahul:Bharti}} \cr & = \frac{Z}{3}: {\frac{2}{3}} Z = 1:2 \cr & {\text{Now}}\,{\text{let}}\,{\text{the}}\,{\text{total}}\,{\text{capital}}\,{\text{be}}\,Rs\,X, {\text{and}}\,{\text{Bharti}}\,{\text{capital}}\,{\text{was}}\,{\text{used}}\,{\text{for}}\,Y\,{\text{months}}. \cr & {\text{then,}}\,{\text{Rahul}}\,{\text{capital}}\,{\text{will}}\,{\text{be}}\, {\frac{1}{4}} X \cr & {\text{and}}\,{\text{Bharti}}\,{\text{capital}}\,{\text{will}}\,{\text{be}}\,X – {\frac{1}{4}} X \cr & = \frac{{3X}}{4} \cr & \frac{{\frac{1}{4}X*15}}{{\frac{3}{4}X*Y}} = \frac{1}{2} \cr & Y = \frac{{15*2}}{3} = 10 \cr} $$