A started a business with Rs. 21,000 and is joined afterwards by B with Rs. 36,000. After how many months did B join if the profits at the end of the year are divided equally? Pick one:  A) 4  B) 5  C) 6  D) 7  E) 8
Sol.   Suppose B joined after x months.   Then, 21000 * 12 = 36000 * (12 - x) ⇔ 36x = 180 ⇔ x = 5.   Hence, B joined after 5 months.   Answer 5
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A started a business with Rs. 21,000 and is joined afterwards by B with Rs. 36,000. After how many months did B join if the profits at the end of the year are divided equally?