Krishan and Nandan jointly started a business. Krishan invested three times as Nandan did and invested his money for double time as compared to Nandan. If the gain is proportional to the money invested and the time for which the money is invested and the total gain was Rs. 28000, find the earning of Nandan.	Choose the correct option.
A) Rs.7000
B) Rs.5000
C) Rs.6000
D) Rs.Rs.4000
E) Rs.6500
3:1   2:1   ------   6:1   7 ----- Rs.28000   1 ----- ? =&gt; Rs.28,000/7=Rs. 4000   Answer: Rs.Rs.4000
<result>D</result>
Krishan and Nandan jointly started a business. Krishan invested three times as Nandan did and invested his money for double time as compared to Nandan. If the gain is proportional to the money invested and the time for which the money is invested and the total gain was Rs. 28000, find the earning of Nandan.