The ratio of the incomes of A and B last year was 9 : 13. Ratio of their incomes of last year to this year is 9 : 10 and 13 : 15 respectively. The sum of their present incomes is Rs 50,000. What is the present income of B? A) Rs 32,000 B) Rs 24,000 C) Rs 20,000 D) Rs 30,000 E) None of these