A starts a business with a capital of Rs. 8500. B joins in the business with Rs.8500 after some time. For how much period does B join, if the profits at the end of the year are divided in the ratio of 3 : 1?  Pick.
A) 4 months
B) 6 months
C) 7 months
D) 8 months
E) None of these
Explanation :   Let B joins for x months. Then   A:B = 8500*12 : x* 8500 = 3 : 1   =&gt; 85*12 : 85x= 3 : 1   =&gt; 85*12/ 85x = 3/1= 
<gadget id="calculator">3/1</gadget>
<output>3</output>
3=&gt; 85*4 /85x = 1   =&gt; 4/x = 1   =&gt; x = 4. 4 monthsnswer : Option 4 months
<result>A</result>
A starts a business with a capital of Rs. 8500. B joins in the business with Rs.8500 after some time. For how much period does B join, if the profits at the end of the year are divided in the ratio of 3 : 1?