A and B have monthly incomes in the ratio 5:6 and monthly expenditures in the ratio 3:4. If they save Rs. 1800 and Rs. 1600 respectively, find the monthly income of B  Choose the correct choice from the following choices:
A) rs . 3400	B) rs . 2700	C) rs . 1720	D) rs . 7200	E) rs . 8200

Rationale: explanation : incomes of a and b = 5 x and 6 x and expenses of a and b = 3 y and 4 y then , savings of a = 5 x - 3 y = 1800 — ? ( 1 ) savings of b = 6 x - 4 y = 1600 — ? ( 2 ) by solving equations ( 1 ) and ( 2 ) y = 1400 monthly income of b = expenses of b + savings of b = 4 y + 1600 = 4 ( 1400 ) + 1600 = rs . 7200 answer : d
Answer: D